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Radiant Heat Drawing Water Every Time?

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Joined: Jun 11 2003

We bought our Eichler in Palo Alto in August. The radiant heat system was pressure tested last year with no issues and seems to get the house warm as the winter comes.

One thing I noticed, however, is that whenever the heat pump is running, the system is drawing city water at a noticable rate (I've done lots of elimination to be sure that it is the radiant system that's pulling the water.) System pressure remains fine (around 15), however, when the pump is off as well as when its on. I can't figure out why this is ocurring. The pump does not turn on except when the thermostat tells it to. Any ideas? If there was a big leak, wouldn't the pressure drop when the pump was off? Where's the water going?

I have Anderson coming out late next week but wanted to see if anyone else has had this issue. Thanks for any wisdom!

Joined: Jul 1 2003

I don't have any ideas, but Anderson is one of the several experts in the area so if you get one of the 3 principals of the firm, you'll do well. In any event, your question is intriguing.

(1) I was not at my rediant heat inspection, so I couldn't ask all the "stupid" qustions or get a overview of the piping, controls, etc. So if the system is alien to you, ask all your questions.
(2) The fact that it's drwaing water is counterintuitive to me; I thought the system is closed loop, so during the pressure testing, leaks are discovered when the the loop becomes open at the leak points. If you drawing considerable water because the sytem is losing water, the leak should be very apparent.
Also, with steel pipe systems, I read that fresh water is discouraged because fresh water will oxidize with the corroding steel (old water has already reacted with steel). So drawing water in a copper system is also couterintuitive to me.
(3) At my inspection, Anderon recommended flushing the system because it was 10% clogged (20% needs flushing - - I have copper so new water should be OK). This would suggest that the system doesn't draw water.
Keep us posted.

Joined: Apr 2 2003

Yes, I believe the system should be closed loop so if you are showing water usage when the radiant heat is on then I woud assume the refill valve is triggering (which many don't after so many years).

As tempting as it might be when you have a company onsite, I would recommend getting at least two diagnosis of the problem. Also, while recommendations/referrals are a good way to start, always do your own "santity check" on a company. What does their license record currently show, how certain are they of their diagnosis, what is the worst that can happen if they are wrong?

If you want to know a couple of experienced radiant heat specialist besides the ones lists on this site, drop me an email at eichfan at rawbw dot com.


eichfan at rawbw dot com

Joined: May 8 2003

Are you sure you are reading it from the water meter (near the side walk) or reading the gas meter (next to your house).

If the meter you are reading is next to the side of your house, then it is a gas meter. That would run if the radiant heat is on.

I had made the same mistake when I thought that the "water meter" was drawing water :) (embarrassed when I realized that it was the gas meter).

- Jimmy

Joined: Jun 11 2003

Great info from everyone and I very much appreciate it!
Jimmyip...I think you just saved me a plumbing visit as yes, I am reading from the side of the house.
So much for a 1st time homeowner to learn!

Joined: May 8 2003

Glad to hear that I am not person who got confused about the radiant heat system.

I had Anderson come out to check out the system anyways. Suppose to do it every 2-3 years just to make sure everything looks ok.

BTW, you probably may want to put in a programmable thermostat to control your heat. I found that to be well worth a $40 dollar investment.

- J

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