I have a hydronic system with a sidearm for hot water. Problem is that hot water temp is not consistent. Zone valve is new and I've checked action to insure that end switch is depressed. Water heater temp set at 140-150. Boiler temp 180, pressure 18-20. The zone valve is open because I sometimes get hot water and the valve lever is always open. Sometimes temp at the faucet is 120 degrees & sometimes it's 95 degrees. I suspect that hot water is getting run through the tank when other zones call for heat but it does not appear that the boiler is firing as a result of a call from the water heater zone's end switch. This new zone valve does exactly what the old one did. Any help would be appreciated.

 

Hi, so it sounds like the HWH is a separate zone, how many other zones, and what is the boiler control ?
Post some pics of your controls
Geo

 

If the lever was always open the tank should get extremely hot.
It sounds like a circulation problem. If there is just one pump..... is it coming on when the DHW opens.

 

Thanks for your replies! Much appreciated!

Geo, Yes, HWH is a separate zone. There are 7 other zones besides HWH. I'm not sure what you mean by 'Boiler Control.' The Aquastat? Sorry pix aren't better. It's hard to get to things. Seems to me like it would have been better to run the plumbing back behind the zone valves but this is how it was when I moved in. Also, wiring is a jumbled up mess largely because excess wasn't trimmed off on installation. If I get this problem solved I plan to clean things up a bit.

Pete, Yes, only 1 pump. it's very difficult to tell if it is running bc it's so quiet, though I don't think it's running ALL the time. Since the zone valve is always open and depressing the end switch, it SHOULD be running all the time, right? I do not know why the valve is always open.

As I mentioned, I replaced the HWH zone valve head, not the actual mechanism. When I had the head off I manually moved the valve and it does not seem unusually hard to move so I believe that it is actually open. I disconnected a red wire and the head mechanism activated and closed the valve so I'm confident that the motor and mechanics of the valve are good.

I have had my HVAC guy, whom I really like, out twice. Last time he speculated that there might be a restriction in the line to the HWH, possibly air but it does not make banging sounds. Pressure was set to 13 and he bumped it up to 15. He said that since the pipe from the boiler to the HWH goes first up to the ceiling, then across the room to the HWH, then down, perhaps it requires a little more pressure than normal. Perhaps, but it's been working for a number of years before this problem. Anyway, it worked for 2 days after he did this but then back to 90-95 degree water - sometimes. I took it on myself to increase pressure & I meant to only bump it 1 or 2 pounds but it right away went to 18-19. Not sure how to release pressure but it's been at this setting for a couple of days and so far no blow off of the release valve.

Hope this gives a better picture of what's going on. I really don't know where to go from here. I don't mind getting my HVAC guy out again but not sure he knows either at this point.

Thanks A Bunch!
Bob

 

Unfortunately there are no pics, just curious, there must be an aquastat controlling the HWH, with all zone Tstat’s turned down (not calling for heat) turning the setting up on the HWH should open the zone valve and fire the boiler, likewise turning down should close valve and shut the boiler down.
Geo

 

What zone valves do you have? Unfortunately your pictures didn't come through. If they are Honeywell V8043's then the end switch is not depressed when in a manual open position.

 

Your pictures are private google pictures. You need to make them public or post them here directly.
How-to-insert-pictures.

 

Hi Guys, Thanks again for your replies. Sorry for not responding sooner. I thought I would receive a notification when someone posted to this thread but I did not get anything so I thought no one posted. Just now that I decided to check the forum itself I see there are responses.

I will try again to post the pics but I don't think they will tell you much. Yes, they are Honeywell V8043E valves. The HWH valve is NOT in manual open, but always open by the motor and the end switch IS depressed. I'm not clear on why this should happen and NOT activate the pump or provide hot water.

There is not a separate aquastat for the HWH, just the one for the boiler which is doing it's job keeping the boiler between 160-180 degrees. I think it may be that I don't have a complete understanding of the aquastat because my HVAC guy once pressed a button on it that caused a motor to activate. That motor appears to be connected to an exhaust pipe that I assume is to expel hot air for keeping the unit from overheating. Maybe it also has something to do with the circulation pump? Everything I've read about aquastats say they are just for maintaining proper operating temp for the boiler.

I have NOT tried yet to close all other valves, which I presume I can do by turning those thermostats all the way down. Currently I have the HWH Tstat set at 160 but I have not tried setting down low to see if the zone valve closes. I will try these things today and post results.

Thanks again for your help!

 

Hoping the pics come through this time.

 

Hi, your right, those pics don’t help at all, Tstat for HWH,set at 160* where is the Tstat located? pos a pic of this exhaust pipe, this sounds interesting, is this the flue pipe? Post some pics of the aquastat and model # of it.
Geo

 

Solved! It's been bugging me all along why the zone valve would be always open with end switch depressed yet not triggering the pump so I removed the zone head even though new and replaced it with another new one. Voila! Hot water!

I've had sorta hot before but I've believed that it was due to having other zones call for heat and then get residual heat in the water tank. Since I installed the new zone head the hot water is very hot. Hotter than I can stand on my hand so I'm thinking it's really fixed now and the culprit apparently was a bad end switch in a new head.

Thanks to all who contributed here! Though you didn't come up with the answer, it's still helpful to get others' opinions.

Cheers!
BK

 

Hi, lower that setting on the water heater before someone gets scalded, how is that water temp controlled?
Geo

 

Yeah, it's on the HWH tank. I've lowered it but it's still hot though it's only set on 110. Might need to replace that.

 

Many issues raised by Bob Krus might be addressed with an Out-Door-Reset / aquastat.

ODRs provide more accurate control with seasonal adjustment, optimize the system for a particular building and can save up to 20% on fuel costs.

The installation manual for Tekmar 256 ODR is a help in understanding the features and benefits of ODR.

http://tekmarcontrols.com/images/_li...e/256_d_07.pdf

 

A good overview of Out-Door-Reset features can be found on Quick Setup pages 15 to 17.

The 21 menu items with adjustable settings are a major contrast with simple temperature and delta-T settings on most aquastats.

http://tekmarcontrols.com/images/_li...e/256_d_07.pdf