All inlet valves downstairs are scorching hot. All rads have been bled. First 3 rads on system downstairs are warm but there 4 after that are not.
Welcome to the forum. Although you can post in any forum, the USA forum is here in case of local regs or laws
Very strange allright, presume not something daft like the pump valves not opened fully, they look like gate valves so should be ~ 3 or 4 full turns from fully shut to fully open. There arn't too many things left, the pump was probably changed out without drain or partial system drain down, possible sludge build up but unlikely except the F&E tank was full of crap and drained down into the system. (if system drained)
The possibility of a faulty UPS3 still exists but if so unlikely that air would continue to build up, are you still venting air, you say all rads have been bled?.
CP1 at 3M should not cause any problems and is required for most systems of your size, my system runs at 3.5/3.6M with the (Wilo) pump set to a PP setting of 4.6M.
The possibility of a faulty UPS3 still exists but if so unlikely that air would continue to build up, are you still venting air, you say all rads have been bled?.
CP1 at 3M should not cause any problems and is required for most systems of your size, my system runs at 3.5/3.6M with the (Wilo) pump set to a PP setting of 4.6M.
John, should the gate valve directly under the pump be fully open? The middle of the three you can see in the photo I uploaded yesterday.
Opening the vent screws and getting rid of any air in the rads. (Bleeding the rads)
Not sure about the one with the red handwheel (you would have to trace it but let it be just now whatever its opening is).
The two brass valves, immediately above and below the pump MUST be fully open, get a adjustable spanner or even a pliers and try shutting first, if they are open then you should get 3 to 4 turns to shut, then immediately reopen, ie they must be ~ 3 to 4 full turns open from fully shut.
Last edited:
Yes, all rads are bled - doing it all the time. No air in them.
The way I got the CP2 to work on Sunday (bleed rads, turn on HW, run HW, turn off HW, turn on CH, when upstairs rads get hot, switch them off and pump heat downstairs) is failing on the last part with CP1 as only 3 or 4 of the 7 rads downstairs get the heat - should I switch all off apart from last one and rebalance the rads?
When you bled the rads on Sunday, how much water did you bleed off each?
If no air in them then pointless venting, except that you are getting some heat in them by actually bleeding off a few litres of water which means no circulation or circ pump defective, CP2 at 4.5M even with all rads open (no balancing) should circulate plenty of water to get all/most quite hot, you have another problem IMO.
When you come home and if you find that the pump valves are fully open (and probably are) then may have to check the circ pump.
If no air in them then pointless venting, except that you are getting some heat in them by actually bleeding off a few litres of water which means no circulation or circ pump defective, CP2 at 4.5M even with all rads open (no balancing) should circulate plenty of water to get all/most quite hot, you have another problem IMO.
When you come home and if you find that the pump valves are fully open (and probably are) then may have to check the circ pump.
probably the cold water supply to your HW cylinder.
Last edited:
Thanks John. I have bled the rads but not emptied them per se - when you say 'no circulation or corc pump defective' what else could cause the 'no circulation'? The weird thing is that on Sunday after I changed to CP2 all rads were hot, same Monday but then Monday night the downstairs rads went cold. So that must be an airlock? But there is no air in rads! Given that we have had heat i would guess the pump valves are fully open.
last one - the screw in the pump to deblock - manual says to turn screwdriver anticlockwise, but youtube vids say ant and then clockwise? Is that a possible issue?
That makes sense, an airlock is a distinct possibility, the only way ("new fresh") air can get into the system is through the air vent, the pipe that bends over the F&E (small) tank. Try and tape a container of water (say a few litres) under this vent with the open end immersed in the water and watch it while starting/running the pump or as I suggested earlier on, just get someone to do as I suggested in post #15, do this first mybe.
Turn all the rads off downstairs bar one, get that one red hot. Turn it off. Turn next one on and repeat for rest. It's just airlocking that's all by the sounds of it. If valves are red hot to radiators, then sounds like air. You've not balanced up downstairs have you?
Yes, balanced all rads up and down a few times.
Had a plumber come round. He has checked the pump, the valves, drained the system, rebled the system, checked the feeder tank in loft and it is still the same. He is convinced there is a blockage in the 'return' feed pipe (I am not going to pretend I know what that is) and we need to do a powerflush.
No idea sorry as I was not here. I reckon so as it was a British Gas engineer as we have the home care.
I don't see why anyone would drain down a system just to change out a pump, however we can talk till the cows come home but
I would go way and buy one of those cheap plug in energy monitors on amazon or where ever, remove the pump cable from the terminal box, Connect a 3 pin trailing socket into the terminal box where the pump was, put a 3 pin plug on the end of the pump cable, plug the energy monitor into the socket and plug the pump into the energy monitor and monitor the pump power, that will eliminate or not a pump problem to start with as these pumps have a very high failure rate or inconsistent performance even out of the box, the monitor is only £15 or £20 and very accurate.
I would go way and buy one of those cheap plug in energy monitors on amazon or where ever, remove the pump cable from the terminal box, Connect a 3 pin trailing socket into the terminal box where the pump was, put a 3 pin plug on the end of the pump cable, plug the energy monitor into the socket and plug the pump into the energy monitor and monitor the pump power, that will eliminate or not a pump problem to start with as these pumps have a very high failure rate or inconsistent performance even out of the box, the monitor is only £15 or £20 and very accurate.
Official Sponsors of Plumbers Talk
Similar plumbing topics
We recommend City Plumbing Supplies, BES, and Plumbing Superstore for all plumbing supplies.
