Hey guys just a couple question and just want to get some input. I was wondering what the gpm is in some of your in slab radiant heat systems. I have a feeling my flow is too fast and is resulting in my boiler running more often then it should. I have a three speed circulator and it in set to the fastest setting. Im just looking for ways to fine tune my system because i want to keep my boiler at a higher operating temp. I have a Mesys pellet boiler and at times the system sucks the temp in the boiler down to 140 which shut the pump in the boiler off till it get back up to over 140 where it keeps going back and forth. I have a outdoor temp sensor. the house is 1700 sq feet. and the garage is 1200. the boiler is rated to heat it all. any ideas on how to fine tune would be nice.
Radiant slab questions
- Thread starter tythib
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I use a mixing valve to provide maximum 100F to the concrete slab. The slab has 6 loops of 1/2" pex, flow through each loop is 0.5 gpm, total 3 gpm.. Typical delta-T on the slab supply/return is 30F (100F supply, 70F return). The supply to the slab is controlled by a sensor in the concrete and is set at 61F constant. Btuh to the slab = 3.0 x 30 x 500 = 45,000. Slab is 1500 sq ft.
I found that on my gf 3 speed pump it seemed to work best on speed two.. I tried the other two speeds but could not "really tell" ....last nite I replaced that pump with the gf alpha ....this morning, while it is running /feeding 4 loops in the shop slab ...flow is 2 gallon and 12 watts..... (auto adapt is still learning) if I ran it full (3 and 45 watts) on it would not push more than 4gpm tops.
I found that on my gf 3 speed pump it seemed to work best on speed two.. I tried the other two speeds but could not "really tell" ....last nite I replaced that pump with the gf alpha ....this morning, while it is running /feeding 4 loops in the shop slab ...flow is 2 gallon and 12 watts..... (auto adapt is still learning) if I ran it full (3 and 45 watts) on it would not push more than 4gpm tops.
Don't trust those GPM readouts on any of the ECM circs. They are basically a calculated flow related to pump rotation. I have seen them as much as 60% off when an accurate flowmeter is attached.
Don't trust those GPM readouts on any of the ECM circs. They are basically a calculated flow related to pump rotation. I have seen them as much as 60% off when an accurate flowmeter is attached.
- Generally in a home the radiant loops run a tighter ∆T maybe 10- 15, so the end of the loop or the part of the slab it serves is sufficiently warm. The Uponor Design Manual shows flow charts for 10 and 20° ∆T
BoilerMan
Minister of Fire
What water temp are you feeding into your zones? Fixed or variable?
What type of boiler return temp protection is installed other than the pump aquastat on the boiler?
What type of boiler return temp protection is installed other than the pump aquastat on the boiler?
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I got a grip on my system !! I was always thinking this / doing that ...to night me and mama via>(walkie talkie) did a test and I found that the alpha pump up ""''top""/60 feet up hill /19'elavation and back > was BS'ing...I changed my speed up there... and my DT IS 11 DEGS 
I was spending to much time at the manifold etc... thanks again for getting me on the rite track.... = do not trust what u see.... or government at any time 
I was spending to much time at the manifold etc... thanks again for getting me on the rite track.... = do not trust what u see.... or government at any time
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Karl_northwind
Minister of Fire
is this the Re-labeled Windhager? a quick back of the envelope diagram would be helpful. there ought to be a mixing valve somewhere and some boiler protection besides the circulator somewhere else. this will help sort out the issue, if there is one.
FYI I end up running most in-concrete tubes 1/2" between 200 and 250LF, about 100 F, and about a 15 degree temp drop and .5-.6 GPM. (based on flow meters on the Uponor EP manifolds)
karl
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no it is a okefen boiler. the water supply is through mixing valves and the temp is controlled by the outdoor reset. usually sends between 110-120 degree water
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