Some warmish Radiators until hot tap is run then all but 2 All aspects of plumbing questions and answers, help, tips and information

[quick]

I’ve got a 7 year old house with a sealed system (so I’ve been told) and a 18 month old condenser boiler which I had put in (the old one was burning gas like there was no tomorrow and then broke). The new boiler is in the garage.

Since then I’ve had a number of problems and I don’t know what to do or what to get a professional in to do.

My issues are :
1 – My system does not really get piping hot water into the radiators until the hot tap is run. I don’t remember this happening until I put some insulation around 2 of the pipes coming out of the boiler, but I’m not saying it did not happen before. Would this cause this type of problem?
2 – Once the really hot water starts flowing the tops of the Radiators get nice and hot but the bottoms of them are noticeably cooler. I always believed that they should be a even temperature from top to bottom.
3 – 2 of my Radiators never get above warmish, one down stairs and one in the room above it. They are not the furthest from the boiler but I think they are the last to get any warmth so I assume they are at the end of the system.

Any suggestions would be appreciated and I’d put my DIY skill level as very basic.

Thanks

[Steve the gas]

Hi Quick,

1. No I wouldn't have thought so
2. Could be pump, switch speed up.Could be sludge -rads need flushing.
3. Balance the system.

Also diverter valve could be the fault.

Hth

[quick]

Thanks for your reply Steve the gas.

I've got a follow on question, which I think I know the answer to based on evidence but I need to ask anyway.

Does it matter which side of the rad a thermostat valve is on? By that I mean on the inlet pipe or the out pipe.

All my warmish ones have the thermostat valve on the inlet pipe and all the others have it on the out.

Also, the none Thermostat valve, should this be wide open or partly open?

Thanks

[Steve the gas]

If your TRVs are bi-directional it doesn't matter, but I would swap around to check result.
The LSVs are opened/closed to balance the system.

Hth