Radiant Floor Heat Troubleshooting
Last Post 08 Oct 2018 06:31 PM by scottishjohn. 18 Replies.
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itscoldoutsideUser is Offline
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06 Oct 2018 10:14 PM
I've got a 30 year old system that I'm trying to troubleshoot. 4 zones - each controlled by a 2 wire thermostat. Only one thermostat will turn on the boiler. Once on all zones will heat so all valves are open. The good news is that I have heat for the winter. The bad news is that I have to heat the whole house because the zoning isn't working. Looking for suggestions on where I start troubleshooting with the goal of getting each zone to work on its own.
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07 Oct 2018 09:29 AM
any have sensible electrician should be able to sort that --basically all the thermostats/zone valves need to be wired in parallel-.eg power to all thermostats -thermostat says on ! that goes to zone valves and zone valves turn on pump/boiler when they open--4/5 wire zone valves
If pump /boiler is too large load for zone valve contacts then put relay in circuit after zone valves but before pump+boiler --job done and thats how it should have been done 30 years ago. I had similar problem when it was fitted by supposed heating specialists-- no relay so zone valves kept failing every couple of years on the load contacts - check current/load rating of your zone valve switches -- most are border line for initial start up load of both pump+boiler.but if boiler system is 30 years old maybe time to think about an upgrade of that -30 years ago boiler efficiencies were half of what a new one would be
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07 Oct 2018 01:19 PM
A new boiler was installed 4 years ago so I'm good there. When the valves fail do they fail in the open position?
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07 Oct 2018 03:34 PM
We will need more info to sort this out. Did the system previously work and it only recently stopped working? How is the zoning actually accomplished, zone valves or actuators on each circuit loop? Normally the thermostats communicate to a zone control module that then communicates to the zone valves or actuators and the pump/boiler. Is that the case here? Most zone control modules have LEDs that help troubleshoot if the thermostats, actuators and zone valves are working.
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07 Oct 2018 03:58 PM
Most zone valves fail closed as do actuators, the motor is used to open them. Most zone valves will have a manual lever on the side to hold open, actuators do not.
You might be well served installing a Tekmar Zone Valve Control
Four Zones with Priority.Part# 304V Tekmar 304V
Instructions are clear it will provide independent energy to each valve, you can also place a individual thermostat on each valve if you are inclined.
It will also control the boiler, should you have a contemporary condensing boiler there is a function in the Tekmar to modulate boiler out put.
Dan
Dan <br>BlueRidgeCompany.com
sailawayrbUser is Offline
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07 Oct 2018 04:34 PM
And Uponor has a similar four zone control module too:

Uponor A3031004
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07 Oct 2018 05:54 PM
Wrong,
Uponor is not similar, not even close.
No line voltage connection, no system pump control, no pump exercise, no transformer, no boiler modulation control. Boiler control is a huge feature if you have a compatible boiler unit as it senses and controls boiler out bound temperature based on actual thermostat demand, beyond out door reset.
It is a long list of differences that continues beyond what I have highlighted. We are so impressed with the Tekmar controls that we are now providing these controls with nearly all of our prefabricated hydronic system panels.
Here is a link to their document.
http://media.blueridgecompany.com/documents/Tekmar306V.pdf

Dan
Dan <br>BlueRidgeCompany.com
itscoldoutsideUser is Offline
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07 Oct 2018 06:01 PM
Posted By sailawayrb on 07 Oct 2018 03:34 PM
We will need more info to sort this out. Did the system previously work and it only recently stopped working? How is the zoning actually accomplished, zone valves or actuators on each circuit loop? Normally the thermostats communicate to a zone control module that then communicates to the zone valves or actuators and the pump/boiler. Is that the case here? Most zone control modules have LEDs that help troubleshoot if the thermostats, actuators and zone valves are working.


I'm told the system was working as expected last year. The crawlspace was cleaned out and a new vapor barrier installed so it is possible something happened during that work.
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07 Oct 2018 06:18 PM
If the rest of the system is 30 years old then i doubt there will be any sort of fancy control module fitted -- I looked 20 years ago for such a thing -there were none on the market -other than silly priced industrial units . not for simple domestic system., simple to check whats going on -cycle the thermostat and see how many valves open up when boiler fires up -the electric control head will just fixed onto mechanical valve by 2 screws -lift them off and watch what happens ,or check if manual lever is loose it will be under tension (sprung loaded) to shut valve when no power is applied
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07 Oct 2018 06:40 PM
Clearly I have Zero knowledge of this persons system, how it is laid out, what model zone valves are used, what boiler is in place and so on.
If it is a 30 year old system zone valve control units were not common, Old school was to drive the motor with an was switch from a separate transformer, the thermostat would trigger the boiler and motor energy.
I wired quit a few like that or some such way way back when for many years.
Correct, check wires see if motors work on the valves, manula open what can be , due diligence.
Just saying for improvement ZVC boxes make it easy and clean. The Tekmar box is $131.00 for a 4 valve unit, $173. for a 6 valve unit
http://www.blueridgecompany.com/radiant/hydronic/702/tekmar-temperature-control-solutions
There are other on line vendors as well that offer these units.
As to the clients boiler again who knows the model, the clue we have from the post is the boiler is 4 years old. So possibly compatible with the feature of boiler modulation.
Even so if not and there currently is no Zone valve control unit it is not a bad thing to improve this system as well if a person is so inclined.
Makes diagnostic work easier, provides better sub zoning control, and the benefit of a host of other features in the ZVC box its self.
That all good for a reasonable sum.
Dan
Dan <br>BlueRidgeCompany.com
sailawayrbUser is Offline
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07 Oct 2018 06:53 PM
The Tekmar has nice features for sure if you need and can actually use them. The Tekmar is also nearly twice the cost of the Uponor.

Yes, it is entirely possible that some wiring was damaged. I would be surprised if all those thermostats/actuators/valves failed in just one year. I suspect that scottishjphn is correct that there currently isn’t a zone control module, but it would be good to confirm that. Perhaps try what scottishjohn suggested. You could also swap the working thermostat with the others and see what happens. As Dan and I indicated, having a zone control module would make troubleshooting much easier.
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07 Oct 2018 07:24 PM
You will still need to provide 24 volt power to the low cost uponor relay.
You will not get any benefit but make break control with led lights 4 zones for $84.00
Where is the transformer, what additional cost factor is there to house, wire , and install the transformer?
Re-use the old transformer? Is it also a 30 year old unit? Only to fail sooner than a new one?
Where are the benefits of boiler management control, pump exercise, and all other features (a lot) for the additional $47.00
You cant even buy the transformer and proper mounting housing for that. There is no comparison.
Like comparing a KIA to a Audi, yes both have 4 wheels, then there are the differences.
I prefer to spend the extra $47.00, have an easier install time/money. System control now will be set with features to use now or later, clean the electrical mess in the mechanical room.
There is a lot of bang for the buck in the Tekmar that supports $47. additional.
Just my opinion that is all,
Dan


Dan <br>BlueRidgeCompany.com
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07 Oct 2018 07:41 PM
We are an engineering design/build company and we don’t sell HR hardware like you do. We do buy a lot of HR hardware from our affiliate SupplyHouse and we pass on those savings to our build clients. These days you can also buy boilers designed expressly for HR that include all the features of the Tekmar and more avoiding the expense and hassle of needing a HR panel altogether. So we don’t have an interest in your marketing/sales agenda and we sincerely wish you all the best. I also share your opinion that upgrading the OP’s HR system would be a good thing. However, the OP might just first want to get his HR system up and running quickly and at minimal cost given that Winter is quickly approaching...and it might be as simple as just fixing some wiring or replacing a couple components...
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
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07 Oct 2018 07:55 PM
Always with the back noise on this Blog,
It always appears as your private help/opinion line has for years now.
Why I stopped commenting as a regular here.
I am just pointing out products. Your Uponor choice is the cheapest possible solution, loaded with ZERO features for 85 bucks. I prefer better. That all.
When I described the Tekmar product I also clearly stated they are available on line assuming that there are many eCommerce sites. Perhaps I am wrong?
Yes Supply house has good prices,
We all try to offer solutions that are good.
Your assumptions about my agenda are messed up,
But perhaps I should be grateful.
By for a while
D



Dan <br>BlueRidgeCompany.com
sailawayrbUser is Offline
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07 Oct 2018 09:05 PM
Sorry you feel that way Dan. I merely pointed out that Uponor also has a “similar” four zone control module. I didn’t say these zone control modules were “equivalent” in functionality. While the Tekmar certainly has more features (which may not even be needed or can even be used), the Uponor provides all the basic functionality needed for a zone control module. Your response “Wrong, Uponor is not similar, not even close” could be taken as hostile. Even when I chose to ignore that response, you still felt the need to turn this into a hardware debate. I for one value and respect your opinion and I even said so previously. I hope you will hang around and continue to contribute.
Borst Engineering & Construction LLC - Competence, Integrity and Professionalism are integral to all that we do!
itscoldoutsideUser is Offline
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07 Oct 2018 11:10 PM
Posted By scottishjohn on 07 Oct 2018 06:18 PM
If the rest of the system is 30 years old then i doubt there will be any sort of fancy control module fitted -- I looked 20 years ago for such a thing -there were none on the market -other than silly priced industrial units . not for simple domestic system., simple to check whats going on -cycle the thermostat and see how many valves open up when boiler fires up -the electric control head will just fixed onto mechanical valve by 2 screws -lift them off and watch what happens ,or check if manual lever is loose it will be under tension (sprung loaded) to shut valve when no power is applied


Each zone has its own thermostat. The issue is that only two thermostats are turning the boiler on (that's an improvement, I put new batteries in all the units and got one more working). All zones have heat because the valves are open. If there's a control module I haven't found it yet. All the valves are in the crawlspace so not easy to see what is going on when I cycle the thermostats but I'll get someone to help me with that so I can provide more information.
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08 Oct 2018 12:06 AM
I would be surprised if so many valves have failed open. As Dan indicated, they normally fail closed. Sort of makes me think that they are somehow miss-wired such that they are all being commanded open and the thermostats are only turning the boiler on. It could well be that the system was never wired correctly. Yes, getting someone under the crawl space while you turn on/off each zone using a good thermostat should shed some light on what's wrong.
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itscoldoutsideUser is Offline
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08 Oct 2018 05:53 PM
One of the thermostats that won't turn the boiler on does control the valve for that room. The others are more challenging to test.
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08 Oct 2018 06:31 PM
do you have a wiring diagram for these valves? -should be able to download one from makers site --then it might make more sense.
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