FP1 Faults & Lockouts

Hi there,

We have a Climatemaster Genesis 3-ton water source heat pump, open loop system that takes water from a pond adjacent to the house. The system has ben running okay since it was installed 2.5 years ago but, on occasion, have had to "steal" a bit of water flow from our well by connecting a garden hose to the intake side of the heat pump to get it to keep from locking out.

Every time the system has locked out, since it was installed, it's been a code 4 (FP1) on the CXM board. The water temperature from the pond is 40 F and it seems if I can get decent water flow to the unit it runs fine. I'm assuming low GPM can cause low water temperature lockouts, is that correct? Right now, if I don't steal water from the well The two Grundfos pumps (1 in and 1 out) will only cause a reading of 3.5 GPM which I know is low. Accounting for water temps, etc. I think I should try and get somewhere between 7 and 10 GPM. I think 10 GPM should make for a more efficient system all around? Would that be correct?

When I start the system, the unit runs for about 5 minutes before going into 2 retries and then lockout. During that 5 minutes the unit is producing heat from the vents but I'm assuming the low GPM might not satisfy the heat pump's requirements, etc.

If I connected a small gas-powered water pump to the inlet side of the heat pump and got the flow to read about 10 - 13 GPM would this be a good place to start in terms of starting to solve this problem? This whole December weather thing is really getting in the way of a warm house without the heat pump functioning and the kerosene heaters are getting a little old after 1 week.

Any thoughts and suggestions are greatly appreciated.

 

Simply put, lower water flow allows the water to remain too long in the coil. Too much heat is pulled out, and the water can freeze. Pulling from a pond exacerbates this problem as you start with cold water and can not add antifreeze to it.

So, yes, increasing water flow is really your best option for your setup.

 

I think I might need a bigger pump(s) then. I just want to get this dealt with. Is there such a thing as too much flow? Will it hurt the heat pump? I'm thinking of hooking up a 1" water pump from the pond and hooking it up to the hose fitting that is on the inlet side of the heat pump and then, if the flow is there, testing the system. The little 1" pump would bring about 40 GPM to the mechanical room where the heat pump is. Does this sound like a feasible experiment or am I over-simpliying?

Also, I've been looking through the installation specs on Climatemaster's website and there is supposed to be a pressure tank, filtration, etc. installed in the system and company that did my system has none of that. What does the pressure tank do for the heat pump? It doesn't spec a size of pressure tank, though. I've also noticed that the mechanical room has a whole bunch of 90 degree elbows in the inlet and outlet piping. Should the 90's be kept to a minimum for efficiency?

I've come to find out that the guy that did our system doesn't know a lot about water-to-water geo systems. They say what doesn't kill you makes you stronger. So, if I can straighten this thing out, my wife and daughter won't kill me and I should be stronger, right? lol!

 

Full disclosure - I have no experience with open loop pond systems as they do not work in my climate. Period.

But the more you are detailing your setup, the more worried I am. Is there drainback prevention on your setup? Or can the system be starting up with air in it? Is it noisy? Pumps really hot?

The drawings you are referencing - are they for an open loop system (well) tied in to domestic?

The main data at this point that is important is what is the flow (generally measured as pressure drop across the unit) and what is the incoming and outgoing water temperatures?

 

I've got a check valve at the mouth of the intake which is suspended about 12" above the floor of the pond which makes it 6 feet deep. When the system starts up and the water is flowing through the clear flow meter on the intake line, there is no evidence of air bubbles in the meter's viewing area.

How do I measure the pressure drop across the unit and how do I measure the incoming and outgoing temperatures. Do you mean the water temperatures at the mouth of the intake and the end of the pipe on the outgoing side?

Thanks

 

Usually there are p/t ports installed that allow you to measure pressure in temperature inline. Doesn't sound like there are any. You could measure temperature just by holding a thermometer along the pipe as close to the inlet and outlet side of the heat pump (wrap it in insulation). Flow could be measured with a bucket and a stopwatch assuming your plumbing allows it.

If you do end up doing any plumbing fixes, make sure to install p/t ports.

 

Bfuller where are you located?

So what you are saying is that you have 100% unfiltered pond water running through your heat pump?

 

Hi Johnny,

We live in the Greater Vancouver area of British Columbia, Canada.

Yes, it looks like the installer never did put in filtration and a few other things that Climatemaster recommends in their website, as I mentioned above.

Unfortunately I've had to intervene as the consumer on this one. I'm hoping to do a test on the system this week where I put some sort of temporary pump on the end of the intake, in the pond and do a test that way. I haven't had a problem with sediments thus far and my flow meter shows no signs of air in the system when it IS running.

I'll pull the intake out if the pond today and measure the thread size on the check valve and go about trying to outsource a pump rental for my testing. I want to test it from the pond intake to give me a true indication of the heat pump's performance as if I pump through hose on the ground I'm assuming my water temperature will drop quite a bit on the way to the house in the 150' of hose it takes to get to the heat pump. I want to try and do some testing first so I don't end up wasting my money on unnecessary pumps.

Last night I tries a 1/4 hp electric submersible pump through a garden hose to the intake of the heat pump but was only able to get 4.5 GPM and the heat pump locked out as it did before. But with 40 F water coming in, Climatemaster's website recommends 2 GPM minimum to pull heat from the water.

I'm hoping I can set something up as running little heaters, etc. in the house will annoying pretty fast, not to mention expensive.

Any other suggestion and comments are greatly appreciated.

Thanks again.

 

One other things I forgot to mention is that when I talked to a guy at a pump shop in town, here, he recommended I size a 4" stainless steel well pump and suspend it in the pond but I think our city inspector would have a problem with us suspending an electric submersible pump in an open pond. I like the idea from a straight pumping water perspective, though.

Right now the original pump configuration is still in place with 2 - Grundfos UPS26-99FC pumps in the system. One is on the inlet and one is on the outlet. However, I've noticed that the two pumps are installed different from one another. One pump is installed with the flow moving horizontally (outlet) and the other has the flow moving vertically (intake). The pumps specs say that it is rated from 0 - 33 GPM but with both pumps on the 3rd speed I'm still only mustering 4 GPM.

Now, I've had to talk to a Grundfos tech last week as my outlet (horizontal) pump was buzzing pretty badly and it was so hot I couldn't even touch it. So I replaced it with a new on and while on the phone with the tech from Grundfos he stressed to make sure the pump's water flow was installed in the horizontal position.

After replacing the outlet (horizontal) pump I was able to get about 1/2 to 1 GPM more out of my flow meter, taking it up to 4 GPM. Specs for this heat pump state 2 GPM minimum for intake water below 45 F so my goal for this 3 ton heat pump would be somewhere between 8 - 12 GPM.

Any thoughts on the pumps topic?

 

I agree, 2 GPM would be the target minimum, maybe more. Never mind the Climatemaster diagrams, a lot of the features you are missing are optional.
While I'm not crazy about un filtered pond water in your heat pump, the Climatemaster trainer had the best line about filtration- "if you need a filter, you should probably go closed loop". I don't think you need to get too fancy, just a few more GPM.

 

Now I am worried. Open pond loops are not done in BC because our ponds get too cold. Overpumping might be the only possibility to get you through this winter.

Iff you can't go closed loop, I would suggest using a heat exchanger in line so you can have antifreeze on the equipment side. This involves more pumping setup, a temperature off, etc, but a frozen heat pump is a large bill.


I'm off to a remote site today, but you could contact me directly later this week.

 

Hi Joe,

I'm assuming you mean 12 GPM and not 2? So, how much flow restriction do 90 degree pipe fitting make? I see a better way of running the piping that would eliminate about 6 90 degree elbows from the 1" pipe route the installer chose. Right now there are 14 90s including inlet and outlet pipes.

Thanks

 

Hi Urthbuoy,

Can you send me a quick link as to what you mean by heat exchanger? Is it gas powered or electric? Are they efficient, etc.?

 

Heat exchanger

 

You loose a few degrees with a heat exchanger, and at 40F you have not much more to spare.

(2) 26-99 on the source side should provide you more than enough flow, actually one should be plenty. So something is wrong with your flow, either the pipes are too small, it is plugged up somewhere, or your distance to the pond is too long.
How far away is the pond, how sure are you that the intake is not plugged up, and what size is the pipe coming in from the pond?

You can simply cure the problem in putting in a well designed closed loop in the pond.

 

I would be suspect of those pumps on an open loop. They don't have much head depending on the lift required.

 

docjenser - When the system was installed, the company brought 1 Grundfos 26-99 for the install. When they installed the piping and pump the flow meter was barely getting 1-1.5 GPM. That was on the day of the original install. Then I went to the installer's supplier to get the second pump and they installed it on the outlet side. That seemed to help, although, I remember still having to steal from my well, on occasion, to "top up" my GPM so the heat pump wouldn't lock out. I think seems like they were oversimplifying things, though. Once you add a second pump to a system isn't there some physics/math involved that would have to be implemented to prevent one of the pumps from cavitating? Anyway, that did seem to help, however, I did have to replace the one Grundfos pump on the outlet side due to overheating/"buzzing" from the pump. The new pump seems to run cool and quiet.

To answer your question, there is approx. 140' of pipe going from the foot valve at the mouth of the intake to the heat pump and the pipe is 1" (i.d). I'd say the total vertical lift from the foot valve in the pond to the heat pump is 10' max.

UPDATE: Okay, yesterday I went to the rental shop and got a 2" submersible pump that says it is rated for 60 GPM. I'm not a pump guy so I don't know the actual numbers for friction loss, etc. Anyway, I reduced the outlet size on the rented pump down to 1" to fit onto the end of the intake pipe in place of the foot valve, put the pump in a large bucket with a homemade screen, etc. and placed it about 2 ft. deep in the water. (Normally I have the foot valve 6-8 ft. deep) With the temporary pump working together with the 2 Grundfos pumps in-line, my GPM went from about 3.5 GPM to about 5.75 GPM, but the good news is that the heat pump hasn't locked out since and is maintaining a very comfortable 70 F in the house. As I write this the outside air temperature is 2 C and the water temp in the pond remains at 40 F. As I write this at 2 am the heat pump just kicked on about 10 minutes ago and sounds smooth and the heat from the register here in the office feels nice and warm.

Obviously this is the desired effect but I'm thrown for a loop (pun intended) as to why I can only get to 5.75 GPM with 3 pumps churning away? It kind of flies in the face of efficiency but I think we've established that lack of flow has been the main issue, here. When I put the rented pump in place of the foot valve I shone a flashlight into the intake pipe and it was literally very clean. I was impressed as it sits, suspended about 7 ft. deep in the pond, 24/7.

Anyway, that's what's happening right now. Now I just have to figure out how to get about 10 GPM to the heat pump with one water pump. I plan on using the rented pump for a week or so to get me through this situation, though.

Any thoughts, moving forward?

Also, btw, I REALLY do appreciate all the great feedback from you guys. It's great to know there is a life-line to finding a solution to problems like this! Thanks again!

 

The reason you only get 5.75 GPM with 3 pumps is that amount is all that will fit in a 1" pipe.

Burnham's "Hydronics Heating Helper" says The most GPM you can get out of 1" is 7.1 gpm at a delta T of 20*F. The "Grundfos Handbook" says the gpm is 6.5.

You need bigger pipe to and from the pond. The numbers above do not take into account any system clogging or fouling. From commissioning you have not had the gph required for your machine.

If you upsize to1 1/4" pipe Burnham says 16.0 gpm and Grundfos says 16.3 gpm. Go up to 1 1/2" and the available flow goes to 24.0 and 22.9.

The 90 degree fittings add about 5' of length each.

Take the third pump back to the store and trade it for a roll of 1 1/4" pipe and a shovel.

I know the fittings on your heat pump are 1" FPT, but from the fittings to the pond I would use at least 1 1/4" pipe. While you are at it add the "Y" strainer CM calls for to the piping. You might want to clean the machine while you are messing with the plumbing.

I hope this helps.

Mark

 

Apologies I meant 2 GPM/ton. That may fare you well if you do not get below low 40F EWT. But I agree in BC it is an ambitious design.

 

Mark,

Finally the pieces of this system puzzle are coming together! It's funny, or not, that my goethermal contractor that installed this system always insisted that it was designed properly. My background is in soil structure and horticulture and hardscaping. One of the first things I learned 20 years ago is that each "system" of plants and ecosystems must work together to accomplish its goal. This thread, in my opinion, is testament to that concept. Obviously this contractor did his consultation based on the given properties of site but failed in marrying the plumbing part of his install with the heat pump and the necessary GPM that a given pipe size can accommodate.

What I'll do today is go out into the pond and see what diameter of pipe is actually in the pond as I know it's the same diameter that we dug 6 ft deep underground to the house. With any luck he reduced the pipe size to 1" at the house and all I have to upgrade is the interior pipe which will be easy to access and replace.

Now, once I do upgrade the pipe to the 1 1/4" pipe should the two Grundfos 26-99 pumps that exist in the system do the job? My instincts tell me that a 20 GPM submersible, controlled by the heat pump would be a better option. I just like the idea of pushing water from the pond as opposed to pulling water from the house. Another thing I've noticed about the pumps is that the one pump on the intake pipe is installed with vertical flow and when I spoke to a Grundfos tech, on the phone, he said both pumps should be installed horizontally. I'm thinking that must be having an impact on things.

Also, right now there is a vertical flow meter on the intake side of the heat pump. When I re-run new pipe it will be low to the floor of the garage and mechanical room. Is there such a thing as a flow meter that I can mount in-line with the pipe running horizontally?

Thanks again, guys! The plot thickens!