WF Series 7 Desuperheater E15 HW Limit Faults

I'll give it a try. You know that I find it hard to understand how a DSH can be installed without a buffer. I'll keep you posted on the effort.

Update: I just looked at their installation manual for their new SM series. They only have single tank instructions in there. Not even dual tank as an option. Must be their FHP background/roots....I'll send them an email tomorrow.

 

Yikes.....from bad to worse.

 

This is making me think it would be nice to start a wiki for equipment manuals. Allow them to be open-source edited. We can take the convoluted and ambiguous text that an undergrad wrote and a committee reviewed, and clarify it. Using our worldly servicing experience.

It is not just the DSH plumbing figures that have issues in many cases.

 

Joe, where did you purchase the AID tool? what was cost? Thanks!

 

I'm getting a 5-series installed shortly with a buffer tank. I thought the AID tool was part of the WF system.
I specified I wanted two - one for the mechanical room by the furnace and one upstairs where it'll be noticed
versus treking up/down stairs everyday or more. Well, I'll get one - not a long enough AID cable is being
made. Sounds like I'll have to fabricate one and put the AID upstairs on an easy-to-remove mount.

Cheers!

 

My understanding is that the aid too is for the tech's n not the owner. The wf cones w a port that the aid plugs into. In addition to diagnostics the aid tool will allow parameter changes n the pri reason why it is not 4 sale 2 consumers. It is such a shame that wf does not have a consumer display that will show things like ewt and lwt 4 the loop, in/out air temp, etc.

 

Joe,

I purchased the AID tool from my installer. It was a pre-requisite for buying the system. It is a very informative tool for seeing information and how the system is performing.

 

Have you resolved your E15 error? I have the same problem and was wondering if you figured out the problem??

 

There is not necessarily a problem. It only means the system has disengaged the DSH pump. From Waterfurnace-

E15, Alarm Hot Water - Fault is recognized when the hot water

temperature sensor is either over the configured limit or the Aurora

has determined the current conditions should disengage the hot

water generation capability limit.

 

That is what WF is saying but the water temperature never gets close to 130 F. It disengages at 98-102F (outlet temp) and the set limit is 130F. If the DSH pump would work correctly the temp would be evenly distributed and would not cut off early. I feel that somewhere the temp does reach 130F.

It did notice that in the heat cycle, water temperature gets up to 130F. and yes I do have a buffer tank.

 

The Aurora system is comparing refrigerant discharge temps with entering HW temps to evaluate the potential to contribute to your HW system. When refrigerant temps are not significantly higher than HW temps the DSH pump will be disabled. This is normal operation.

 

Do you have the parameters for these conditions??

 

It could be a bad sensor, which had happened to me a couple times. Have your service technician check the indicated temperature on the aid tool, to check what temp the control board is seeing so it throws that fault code.

If it only does that in cooling mode, and you are up in Canada, chances are that your loop temps are too low to generate hot water above 100F. It simply turns of the pump not to transfer heat from your tank via the refrigerant circuit into your loop. This has happened when the switch to R410a was made, and many manufacturers were caught be surprise. WF has some logics built in that it limits the tank temp so heat is not transferred from the tank into the loop in cooling mode.

Does not affect heating mode. Sounds like that is what you are seeing.

 

I did check the temp sensor and it is working correctly. Did all the troubleshooting where I would disconnect the Temp Sensor, move the sensor off the copper pipe and replace the temp senor all together. We determined that the high temp E15 is not coming from the DSH outlet. What other sensor are there that would give me the E15? My loop temps run around 60F. Would like to know if I could bypass the DSH pump and have it remain on high for testing purposes only. Something is tripping the overtemp sensor which gives me the E15.

 

I have Symphony so the WF Tech Support can look at my system and they still can not find out why. I just checked and my loops are running around 61.4 F, I believe that is warm enough.

 

No. I have reviewed all available documentation and the parameters are not published.

I have observed 2 Series 7 systems on Symphony and today they are barely running in Heating stage 1 with Compressor Discharge temps around 107F. These systems do not have DSHs, so I can't help with any other comparisons. I wouldn't expect a tank full of 130F water if your Compressor Discharge Temps are also that low. If your buffer tank is approaching 100F, I would consider that normal under low load conditions.

 

Do you know what other systems will set off the E15 besides the DSH water temp??

 

I don't know how to say it any better

 

That does makes sense. You had to say it twice.

It just gets you mad when the A/C is running at full load (C9), the DSH is starting to heat up your water tank and then it all of a sudden cuts off at 102 F because the Aurora has determined the current conditions are not favorable to make hot water. To tell you the truth, it is more efficient to make hot water via the DSH at any time than using electricity (or gas) to heat your water tank.

 

With 60F EWT at full load cooling the performance charts show a mere 2 to 3 thousand btu/h of Hot Water capacity.
http://www.waterfurnace.com/literature/7series/SC2700AN.pdf

The hot water generator numbers are based on a flow rate of 0.4 gpm/ton of rated capacity with an HW EWT of 90°F.

Your cool loop field while cooling results in lower Compressor discharge temps and less potential to make Hot Water.

With all due respect I think you are chasing your tail on this. But if you wish to carry on, what are your Compressor discharge temps?