Radiant Floor Too Hot!

Old 01-24-06, 06:22 AM
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Radiant Floor Too Hot!

I desperately need to reduce the temperature of the water that my boiler is sending through my PEX tubing. The tube is expanding at a rate of 1" per 10 degrees per 100 ft of line. The system currently runs at 190 deg F, without any obvious controls. I need to reduce that to 120 - 140 to reduce the amount of expansion of my lines which have been ripping their hangers from the joists and floors above.

The boiler is from Vaillant, (Model: GA-92-060 EI), it seems that I havent been able to find a manual or speak to anyone familiar with them. Please help.


Last edited by braxtonlewis; 01-24-06 at 06:34 AM. Reason: Addition of Model No.
Old 01-24-06, 09:54 AM
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Is the underfloor radiant the only type of heat emmitters that your boiler supplies? The aquastat can be backed down to a lower temperature but then your house may not heat itself adequately. There should be proper controls with radiant to keep floors from going over 85*. I have no knowledge of Vaillant boilers (British company) but if it isn't a condensing boiler then you need to set up some kind of mixing or injection piping for the radiant to protect your boiler, you can't run it as low as 120* without it corroding prematurely.

I'm not sure how quickly you can become on expert on this, but if you can't then you should get one in and pay them to assess your heatloss, the system you currently have and how it could be improved. Then you could decide whether the scope of work is something you feel comfortable doing.

It sounds like you inherited someone else's problems. :-/
Old 01-24-06, 10:11 AM
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I agree with Who. Radiant floor heat system should have some type of mixing valve/control to temper the water for the floor.

Was this just installed? If yes, I'd go back to the installing dealer and get this installed the right way.

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