Radiant in floor heat

MikeB34

I have a customer whom I maintain their water heaters, gas fireplaces and A/C and have soolved many of the original installation problems. They want me to take on their boiler. I have no problem with the combustion side of it as I already maintain that, but they have a problem with the temp from their in floor heating. It seems that when the outdoor temp drops too quickly (which it does here in Canada) their system has to play catch-up and its not too comfortable for a couple of hours. They have a Veissmann vitola boiler with outdoor reset and 4 zones. The zone with the problem is the main floor-open concept are 2 storeys and about 1300sqft marble tile flor. Its a big house overlooking the lake, floor to ceiling windows. The boiler has more that enough capacity. I am a scorch head, not a wet head, so I turn to you all for advice on how to deal with this. I have some hydronics experiance so technical descriptions wont lose me. Thank in advance. Mike

kf_2

A few questions

1. Is the system utilizing constant circulation or are the pumps cycling on and off with a room thermostat?

2. Is there a mixing device for the radiant or is it just running off of the boiler reset?

3. Are there radiant manifolds that have the ability to add, or already have power heads or zone valves for each tubing loop?


kf

Geno_2

You have zeroed in on your problem. Radiant heat does not respond quickly. It also takes a while for you to notice it's down because the floor stays warm. See if you can convince them to pick a temp and stay with it. Setting back or turning down the temp with radiant doesn't work. Pick the temp and stay with it. It's very efficient so it doesn't matter. You are wasting fuel playing catch up.

geno

MikeB34

in answer

1- its constant circ with zoning valves running off of stat
2- I could see no mixing valve
3- no manifolds

I was thinking of mixing the water feeding this zone at a steady temp(80-90deg) and only shutting down the zone when stat is satisfied..will this work?

MikeB34

thanks for the advice..they do have prog stats. another piece of the puzzle falls into place..

Al Letellier

stats and reset

As mentioned before, Mike, you solved the problem with your own information. Programmable stats and outdoor reset just don't belong together. I learned this many times, the hard way and even walked away froma large heating job, becouse no matter what I said, I couldn't convince them that outdoor reset saves way more than program stats. Pick a temp and stick with it is the best advise we can give you. Hope you hear that and convey it to your customer. If he doesn't listen, don't take on the responsibility.

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John Felciano

Viessmann

What control are they useing on the Vitola?

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MikeB34

I gotta go back to check on that 1..

MikeB34

Seems to be the concensus so far. It'll be a couple of weeks before I can get back in to see the guy...he's out of town for a short vaca...But I figured I'd better do some homework. This site was recommended to me by some friends at ECR (utica Boilers) as the best place for info..and were they right. THanks Dan and everyone (I've been checking out other threads) THis sharing of ideas and knowledge is a great thing.

John Felciano

Control

If it's useing the vitotronic there are functions that will turn the system up sooner to help.Check the slope and curve.There is also a nightime setback built into the control that has to be set or the whole system will go into nightime setback.

The vitotronic is an awesome control but can be a pain to program for the first time.

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MikeB34

Thanks

Thanks everyone who contributed. I'll look into the programming, and controls. and I'll deal with the stats.
I appreciate the help, and if I have more questions or info, I'll get back to you all.
THanks Dan for a great resource.

Mike