Upstairs rads r cold appears to be no pressure 2 vent rads
Upstairs rads where cold on bottom warm on top. took them off and flushed the out (lots of thck black oily gunk) the boiler is v old (thorn m b71238/4 ) there now appears to be no water pressure to bleed rads so they are still cold. down stairs are working normaly
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Re: upstairs rads r cold appears to be no pressure 2 vent...
Have you sorted problem yet? sounds as though the cold feed is blocked or as the other guy mentioned an air lock.You can sometimes turn the pump on & off a couple of times as it can dislodge the air lock & shift it allowing you to fill the rest of the system. failing this you can back fill it using a hose connected to the water main & connect to a drain **** either on one of the rads on the groundfloor or on the boiler, once you have filled the rads disconnect the hose & close off the drain point
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We have just had our old system boiler replaced with a vaillant ecotec plus 837 and sounds like a similar working operation to ours. At first I was a little concerned,but I was told by our installer that he was told by vaillant that these very latest boilers size the system on start up for about 10 mins, then take temperature to target flow which you set boiler at.
So even by setting target flow temperature very high you still get the initial sizing cycle, which ours was about 30-35c temp.
These boilers seem to run biased for efficiency as after a while they modulate the boiler burner down and the radiators run more on the side of warm than really hot like the old type boilers. You also get better efficiency as at lower temperature the boiler condenses better. You will also find you get a more constant temperature in your home rather than over shoots.
I was concerned at first, shame there was no info/explanation in user manual as people do need to know that this is normal operation.
We are used to ours now, took a month and by the way these boilers can make a creaking noise but was told this normal expansion/ contraction but annoying when sited in bedroom cupboard.
Best of luck!
Make sure the air is bled from the upstairs rads. [air = top of rad is cold & bottom hot]
If you need to balance the rads to maintain an even flow through all then :- Turn off all rads [one valve fully open and the other closed] Get heat going and open each rad valve, in turn, about 1 or 2 turns. Start with upstairs. The position you need to get to is when the return pipe fron each rad is a few degrees below the flow pipe. Adjust each rad valve to get this effect a few times may be necessary
Sounds like bottom element may be bad but
usually reads open circuit if bad.
Also tan k would run about 8 gallons hot water then go cold.
lots of warm water usually means bad dip tube.
Check if tank is hot at bottom element when not used for a while.
If bottom element is still cold then bad element.
If bottom element is hot - (all water in tank is hot then you have a bad "dip tube"
This is allowing incoming cold water to mix with outgoing hot water.
The dip tube is usually
A part of the cold water nipple or
B located under the cold water inlet nipple.
Carefully catch some water in a container from pressure relief valve (pull lever slightly) at top of tank, and see if it's up to temperature. If it's hot there, I suspect your by-pass at back of the tank, is faulty. Depending on what by-pass system your using, it may be in wrong position, blocked, or mixing hot and cold. Cold water flows into bottom of tank, and hot out the top. If any valve in between the 2 lines, close it, and make sure valves in and out of bottom and top are open. Let me know what you find, or if water from pressure relief valve is not hot either.
Hi, What your looking for is called a (hy-vent). it bleeds air out of a system. you should have one on the top of your expansion tank. it is 1-1/2" in diameter and about 3" long. there is a little cap on top, unscrew the cap off. it looks like a bicycle tire valve. press the stem down inside until water comes out, then put the cap back on leave the cap loose so the hy-vent can do its job. it should be a self bleeder. If this doesn’t work for you, please write back.Thanks,
the problem there a relay stuck or thermostat bring on the pump & you can lower your high limit aquastat!! also the flow valves can bypass hot hot water risers time to put in a seperate water heater domestic coil are not energy efficient !!!! aquastat high limit set @ 180f deg low limit set @ 140f deg!!!
good luck!!! tim