Minnesota Lockout - Low flow?

Discussion in 'Maintenance and Troubleshooting' started by Curt, Jan 19, 2016.

  1. Curt

    Curt New Member

    I am a homeowner. Hydronmodule Colony Series Plus WWD72. One unit for hyronic radiant floor in basement and garage coil. The other unit is for forced air on main floor of home.
    When very cold out and all being used a lot, unit 1 (forced air on main floor) goes into lockout.
    Last year this happened and installer troubleshoot with me there and figured low water flow because of blockage. I flushed through system with "iron out" and replaced a ball valve that was caked/restricted.
    Worked fine with ball valve for source to unit 2 (radiant floor and garage coil) partially closed.
    Has worked until the last cold spell here (-20) and then I see unit 1 going into lockout again.
    We also see a noticeable pressure drop at shower/faucet when both units running.

    Ideas I have: source in lines/valves/flow restrictor restricted, well supply line restricted, pressure tank problem, well pump getting weak (13 years old).

    Ideas anyone? Thanks!
    Here is a diagram of the system.
    Last edited: Jan 19, 2016
  2. Curt

    Curt New Member

    I forgot to say that this is a Open Loop system. Source In water comes in from the well and the Source Out is discharged into drainage area/ditch.
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Could be low flow and your source coils are freezing. What are your temps on the source side? 5 gpm as indicated on the drawing is not enough flow for a 6 ton unit. You should at least have 9-10 gpm.
    Curt likes this.
  4. Curt

    Curt New Member

    Thanks docjenser! I will check temp best I can with a thermo couple on my multimeter, but don't have a gauge. I would imagine that the water will be colder after running a while, as the pressure tank looks to be 50+ gallons.

    The 5gpm on drawing is not what I measured, but on the label of the flow control valve. It is labeled Hays 2510, 3/4" , 5 gpm. (can change gpm flow cartridge 0.50 to 9.0 gpm)
    Your comment saying 9-10 gpm makes sense to me. I found a data/spec sheet for WWD72 and it shows 18.0 GPM for heating and 15.1 GPM for cooling.
    I wonder why the installer (or other person that worked on it...since installer commented that it looked like someone else worked on it after he installed.) installed 5.0 GPM flow control valves.

    It appears that the flow control is one of these:
    It looks like there is 2 P/T ports on the Hays flow control valves. Can I get a gauge that will measure gpm flow across them?

    The image below shows how the source in 1 and 2 ball valves were set (last year when I had trouble and flushed through the source coils.)
    I wonder if previous homeowner had flow issues (in other parts of house?) and tech person set like this to restrict flow.
    It also shows the only gauge installed in the system. It is on the Load Out and doesn't appear to be working (never saw a change). Having never installed a gauge on P/T port, I am not familiar. Can I take the gauge out of the P/T port without water escaping and 1) see if I can figure out if temp is working and 2) If working, put it on in the P/t port on the Hays flow control valve?

    Also, when I flushed last winter, I took apart union, took off Belimo sol/valves and cleaned them out. I also found that the Source In 2 ball valve was 50% blocked with iron/other deposits...so I replaced that ball valve.
    I then used a small pump and washing machine hoses to flush "iron out" solution through source coils (both directions). Lots of rusty looking crap came out. After circulating through, I opened the Source Out ball valve and pumped the the (dirty) iron out and water solution out the discharge (hoping to flush any iron/other buildup out of the discharge pipe). That fixed the issue then, but it was end of winter and problem didn't come back until cold snap beginning of Jan.

    So, other than flushing to get crap out and taking apart flow control valves to clean, should I be reworking this system to make it work properly/better.
    Understandably, I want to diagnose everything properly first. I prefer to find the problem(s) first and then plan the proper fix.
    I apologize for providing so much long winded information, but I'd rather provide too much than not enough. I realize that I may get to the point of finding a good/knowledgeable Geo expert to rework/fix, but want to try and figure it out as much as I can before spending the cash.

  5. Curt

    Curt New Member

    An aside question: I was looking at the Hydron Module Two Stage Multi Position Vertical Packed Revolution Series Engineering Data & Installation Manual (current system on their web site) and saw this info about Hydronic Buffer or Storage Tanks.
    Is my system running less efficient or having troubles because of lack of a buffer/storage tank?

    revolution_typical_buffertank_opt.jpg revolution_typical_piping_opt.jpg
  6. geoxne

    geoxne Active Member Forum Leader

    Does your model have 2 compressors or a single 2 stage compressor?

    I ask because there are 2 flow controls and 2 motorized valves which would be correct in either case. The difference would be a 6T dual compressor unit would have two 5gpm flow controls, one for each compressor to total 10gpm. A single 6T 2stage compressor would have 6 or 7gpm for 1st stage and 3 or 4gpm for second stage to total 9 to 10gpm.

    Iron is the enemy in open loop systems. All manufacturers publish water quality minimums for their units. Iron oxide should be less than 1ppm with no iron bacteria allowed. You will have to setup a maintenance schedule to control the problem.
    Curt likes this.
  7. Curt

    Curt New Member

    geoxne, I believe, but will verify, that there are 2 compressors. The indicator lights are labeled Unit 1 and Unit 2 and appear to operate independently (main floor uses unit 1 - load in 1 and basement/garage radiant use unit 2 - load in 2)
    I am seeing that iron is the enemy. What is not in my diagram is the connection from pressure tank to house.
    From pressure tank, T plumbed to GSHP directly, other side to house. There is a T plumbed to outside faucets and also to cartridge filter, through filter to softener.
    I have tried to change the filter every few months, or when pressure at faucet is reduced. Filter is Hytrex 20" Filter - 5 Mic GX05-20 and they do get filled with iron oxide.
    Having said that, it strikes me that there is no filtration on Source In line(s) to heat pump. Putting myself on a maintenance schedule to flush coils will be done, but maybe I should put a filter inline to be able to change/clean to cut down on what gets to the coils.
    If so, I would imagine that choosing the proper filter to catch the iron oxide, yes still allow 10+gpm flow.
    I'll see if the Hytrex filters I am using before the softener will flow that rate.
  8. geoxne

    geoxne Active Member Forum Leader

    Filtering a domestic water system that flows 240 gallons a day is feasible. Filtering a geo system that has the potential to flow 14,400 gallons a day is not feasible.
    Curt likes this.
  9. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    You don't need buffer tank if you have enough minimum flow through your smallest radiant zone, otherwise yes, you might have not enough flow on the load (radiant) side of your heat pumps. Imagine only 1 zone is calling, and 2 heatpums are tuning on.

    The 18 gpm for heating are for closed systems, open systems are usually half of that amount.
    Curt likes this.
  10. Curt

    Curt New Member

    Having similar issue with this again.
    The unit2 compressor shuts off and stops heating the water that is flowing through hydronic in floor.
    I again went through flushing with iron-out and didn't find nearly the amount of iron/crap that I did previously.
    What happens is when the thermostat calls for heat, the electric valve opens, the circulating pump starts the water circulating through the floor, and the unit2 heatpump comes on (and green light).
    After a minute or so, the heatpump shuts off and green light goes off.
    The electric valve for water coming in from well stays on, and the circulating pump stays on...so water being circulated is about room temperature.
    The ball valves are set similar to the image above, where they are partially open.
    I tried resetting with breaker off/on and turning ball valve full open (only unit2 calling for heat so unit1 water use not a factor).
    The heatpump ran a bit longer and then shut off leaving the water flowing but not being heated.

    Could this be caused by the aquastat that is on the load out going to the radiant floor?
    The setting on it is hard to read but it looks like about 105. I turned it down to 65 and the supply valve closed and circulator pump turned off. Turned it back to 105 and supply valve opened and circulator pump started again...but no heatpump.
    It does look like it has a differential setting (small white plastic wheel set to about 6 marked 5, 10, 15).
  11. Curt

    Curt New Member

    I had the original installer come out and help troubleshoot/fix.
    The control board for the compressor was not working properly...could see burn resistors when opened it up.
    Replaced with new control board.
    Also found that the flow was low and was shutting off heatpump/compressor.
    So, after flushing everything, etc. I am able to run either one heatpump/compressor or the other and get heat...but not both as the water supply is not enough flow.
    Have a 1 horsepower well pump, connected to 1" poly pipe into a galvanized 1" elbow, then 1" nipple into pressure tank (I think 80 gallon).
    The output of the pressure tank is 1" to copper teed off to 1" for house/heat, then to 1" pvc teed off to feed the 2 source(s) to unit.
    Installer thinks that after 13+ years the 1" supply line is built up with iron, etc. and is restricting.
    So, plan is to limp by until spring when I can dig up the supply line from well and replace with a new 2" and replumb all fittings at pressure tank to remove small and/or restricted ones.
    We are also going to discuss putting in a buffer tank on the load side.
  12. Curt

    Curt New Member

    I am adding more to this thread as I am still having "fun" with geothermal. Since the last post on here, we have replaced the well pump (was worn out and pumping only about 5gpm), blown out/flushed line from well to pressure tank in house, and cleaned/replaced all plumbing from pressure tank to geothermal units (and toward filter/softener and rest of house). This greatly improved everything. both compressors can run at the same time and house water flow is great during that time.

    The way the dump side is plumbed is messed up, in my opinion. The outgoing line from the geo units goes up and through the floor trusses, exits the side of the house (4ft. from ground level). There is no insulation on it, it is exposed and is dumped into a 2 inch pipe that is goes into the ground and runs 200 feet or so out into a field where the water just runs out. I don't know how deep it is buried, but I'm guessing not below frost level. I don't know why it is don't like this but I know that the Geo installer had to come back and redo the output differently and this is the result.
    Being in a colder climate, this has led to problems a few times. Twice, the line coming out of the house froze at least part way back into the house. The way I thawed it was to run hot water in from the outside until the frozen blockage was removed. Not fun when it is -20F. The other problem that I have going on now is that the line is now frozen somewhere between where the 2 inch enters the ground by the house and the field where it dumps. We have no snow this year to help insulate the ground, so it probably is making the frost go deeper than normal...who knows.
    Right now I have rigged a big 6" pipe to carry the water that is dumped out of the house 40 feet away into the yard and down a hill. Arrrgggh!

    So, at some point I want to get this system fixed so that this crap doesn't keep happening.
    I am thinking that my best option is to convert to closed loop. I won't have the worries about iron clogging the pipes, I won't have to worry as much about the 1HP well pump wearing out, and if I'm not trying to dump water out through a pipe that is exposed to freezing cold temperatures at ground level, I shouldn't have to worry about it freezing.
    I have the land to do horizontal ground loops.
    Incidentally, I have been thinking about an addition with more garage space. I was thinking of running a small outdoor wood furnace to run radiant floor heat in the garage space. If I end up converting to closed loop and making major changes to heat/cooling system, maybe I could find a way to use the hot water from my outdoor furnace to supplement or have as backup for geo. I'm thinking like a plate heat exchanger on radiant floor loops and set up pump/controls to use wood fired hot water to heat if water is hot enough and to use geo if not. Backup when I have been having these problems so

    Regardless, I will have someone do the work. I can do some DIY, but this would be way more that I want/should do. Especially with installing ground loops, etc. I have a feeling cost is going to suck and make my proposed garage addition smaller. :(
    Back to researching and looking for a good Geo contractor in MN I guess.

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