Thermostat or Zone valve?

E. J.

Hi, I learned a lot about my heating system by reading your
website
article
> on Loop heating system. I would appreciate if you can help me
to solve
these
> problems.
>
> (1) I have Vaillant Gas heating system (with 4
zones/baseboards). A week
> ago, I changed two thermostats in the two zones. And the heat
won't shut
> off in one of the zones. I set 65 degree but it can go up to
73. I
followed
> all the instruction. Since it is a digital, I did not have to
set the
> anticipator. I have to go downstairs and shut the system off
every
morning. I have tried to change the zone valve. It was not the problem.
> What are the possible causes of this?
>
> (2) Before this problem, a tiny button of some sort of sensor
attached on
> the side of venting area (thru the roof) constantly popped out
and stop
the
> heating system entirely. I had to mannually put the button in
and the
> system went on again. Should I change the sensor?
>
> (3) Finally, two drain cocks on two sides of the bottom of the
system are
> leaking (one drop per second). They have plastic drains. Does
this cause
> this problem?
>
> Thank you for your prompt answers in advance.
>
> EJ

Pat Clark

Try this

Turn all your thermostats way down. All zones should close. If the one that is giving you a problem is still heating, remove that thermostat from the wall and make sure the wires are not touching. If the zone closes you may have had the t-stat wires touching each other when you installed it or you may have a bad t-stat. Reconnect the t-stat making sure the connections are good and do not tough each other. If zone operates correctly then your good.

If when you turn all your thermostats down, all zones close, then you want to turn one on at a time and make sure that the correct zone comes on for the t-stat you have turned up. Sometimes the wires get crossed and you have the wrong t-stat operating the wrong zone. This will tell you if they are wired to the correct zone. Do one at a time until you have checked all four. If you find incorrect wiring, it will need to be rewired at the zone valves.

The vent switch is a safety and usually indicates a backpressure problem on the flue stack. This can be a dangerous problem allowing Carbon Monoxide to enter your home. Unless you are familiar with this you should have a professional look at it and make sure it is safe. CONTINUING TO RESET IF THERE IS A DRAFT PROBLEM CAN BE FATAL. DO NOT IGNORE THIS PROBLEM.

The drain valves usually start leaking if they have rubber seats. They need to be replaced which would require draining the boiler. We use ball valve boiler drains which have a much longer life than the typical rubber seated drain valves. Ask for them if you get someone to come out to make repairs, cost a little more but well worth it.

Hope this helps.

Pat

Dennis - Reliable Services

A quick fix for the drain valves is to install brass caps get,

them at Home Depot or a plumbing supply.