Freezing in Colorado - no circulation

Old 12-05-05, 10:17 PM
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Question Freezing in Colorado - no circulation

The First really cold-cold day and the heater stops working -go figure!

I have been reading other people's problems and this forum has already helped me quite a bit - I am learning quite a lot from others, so thanks for all your previous advice and tips.
My problem is that the Heat Zones do not always produce heat when activated. I have a circulating hot water gas boiler. The house is 4 yrs old. I have been attempting to repair this 8-zone system with only partial success. I have done some checks so far and found that all thermostats can actuate the Honeywell valves. The three upper level zones do not always start circulating. I have spent many hours bleeding air from the system. I do this by attaching a garden hose to the return manifold and then open each zone valve one at a time releasing air into a partial bucket of water to see the bubbles. This has restored heat to all the lower level zones and 2 upper level zones. Two upper zones are being stubborn.

I have at lease made the system operate on 5 zones for now. Below are some things I have noticed and some questions. I am wonder if the system was designed correctly in the first place because of re-occurring problems each year and multiple calls to the furnace man.

Info on my system:
1. The Upper level zones are black flexible pipe routed under the flooring (no registers on upper level) these upper zones are fed from a booster Taco pump with temperature mixing T to reduce water temp before water goes into the booster pump. (Why is the "T" there, and why is it only on the upper level zones?) I am suspecting the mixer could be clogged by the large amounts of sediment in the water (noticed this while bleeding) These upper zones have given me the most trouble and two zones are very long runs, 40 ft.

2. The lower level zones are all baseboard type registers and are only fed from the primary circulating pump near the boiler. (No temperature reducing Ts on these zones. Why?

3. Both pumps sound like they are running. The lower pump is very quiet.

4. The system will maintain 20 psi with the fresh water re-supply line shut off. It will hold 20 psi consistently for 48 hrs without any noticeable drop in pressure. I have not noticed any leaks anywhere so far. PSI is now set to 18 lbs.

4. Different combinations of zones coming on at different times can cause other zones to not circulate.

5. I have an expansion tank with an air balder on the return side. The tank has and a manual bleeder on top of the tank. (Similar to a tire valve stem) when I tap on the tank, the lower half sounds hollow and the upper half is filled. (Normal right?)

6. The valves, manifolds, boiler and pumps are all in the basement with easy access.

I can not find any bleeders up high close to the ceiling of the basement (booster pump is up high and I can here gushing noises and previously when the furnace was working well it was very quiet.) I suspect air is in the pump. Would it be a good Idea to add a bleeder up high on the copper pipe? I would rather not drain the entire system and was wondering if there is an easy way to tap the pipe without draining. A product suggestion would be helpful.

Any suggestions on what to try next????

Any helpful web links that describe the function of all the hot water circulating components would be helpful.

Old 12-06-05, 10:16 AM
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Bill, it sounds like you have underfloor radiant upstairs and baseboards downstairs. You don't have temperature reducing T's downstairs because they are not needed for baseboards. They are used in the radiant to keep the temperature around 120 degrees (I think, I'm no expert), but the baseboards should get it at full heat to work their best.

It sounds like you may have air in your system...have you checked your baseboards for bleed valves? They are usually at the end of a cast iron baseboard (where the pipe goes back down into the basement), or in the tubing run, usually after the fins, on a copper tube/fin baseboard. Your radiant system may also have manual bleed valves, but I am not as familiar with those systems. You want to look for the high points in the system. In my basement zone, the bleeders are in the drop ceiling, because that's where the piping comes from and goes back to.

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