Radiator temperature problem

[Piglet]

This might be a really bad description, I'm the non technical member of the family!

Dad's bedroom radiator is the last in the run and we struggle to get his room to a decent temperature for him. The living room hit 25 degrees earlier and his room doesn't seem to go above 20 degrees which isn't sufficient for him so he's running the heating 24/7 and anyone else in the main house is baking!

We have a wall stat in the hallway and all of the rad's but one of the bathrooms have TRV's on them. (for info we've added an extension which OH and I live in, leaving Dad in the main bungalow. The same boiler runs the heating in the extension but on a different circuit and different stat) and the boiler was spec'd to do this.

The wall stat is in the hallway and the adjacent radiator had a TRV on it but we've just taken that off as it appears that won't be helping?

The hallway previously had a single glazed door and glass panel but that has this summer been replaced with double glazing so the hall is much warmer than it was and I suspect this is relevant as we've not had the problem to this extent in previous years.

Is it likely that removing the hallway rad TRV will help or will that just heat the hallway quicker meaning that the heating shuts off before all rooms are warm?

He normally has the TRV's in the living room rads (3 rads) on 5 but I suspect part of the answer is dropping these to a lower figure to allow the heating to run through the rest of the house but to shut off to the rooms that are warm.

Hope this makes some sense! Sorry it's long - 'd be grateful for any advice as we're sitting in a sauna and as it's Christmas we can't FO back to our nice cool extension!

Edited by Piglet on Friday 24th December 20:48

[eliot]

level 5 is essentially flat out. Try turning them down to 3.5

[Globs]

Surely you just turn down the TRVs as required?

[Gingerbread Man]

The radiator in the same area as the room thermostat shouldn't have a TRV on it. They'll conflict with each other.

It sounds like the system might need balancing. The radiators nearest to the boiler should be cranked down via the lockshield, and the ones furthest out from the boiler at the end of the run should be wound open.

Also if you turn all of the TRV's off bar the one in your Father bedroom, does it get hot hot hot then?

While you're checking out the central heating system, make sure the boiler's thermostat is turned up to make it most efficient.

[Piglet]

Gingerbread Man said:

The radiator in the same area as the room thermostat shouldn't have a TRV on it. They'll conflict with each other.

Done now

Gingerbread Man said:

It sounds like the system might need balancing. The radiators nearest to the boiler should be cranked down via the lockshield, and the ones furthest out from the boiler at the end of the run should be wound open.

Lockshield?? Is that the TRV's? So we turn down the nearest ones and turn up those further away and presumably keep tweeking til we get the right result?

Gingerbread Man said:

Also if you turn all of the TRV's off bar the one in your Father bedroom, does it get hot hot hot then?

Yep, there appears to be nothing wrong with the flow etc. and all rads have been bled.

Gingerbread Man said:

While you're checking out the central heating system, make sure the boiler's thermostat is turned up to make it most efficient.

Will send OH to check it.

Thanks for your help

[Piglet]

Hmm just to add a bit more, I think the positioning of the wall stat is a problem. It's quite close to the hall rad and now the hall is double glazed it's getting hot out there very quickly which is turning it all off.

I guess the answer is to use the TRV's to regulate rather than the wall stat?

....or move the location of the wall stat?

[Laurel Green]

Piglet, the lockshields are the the valves at 'tother end of the radiators. Usually a white plastic cap, sometimes held on with a small screw.

[Piglet]

Laurel Green said:

Piglet, the lockshields are the the valves at 'tother end of the radiators. Usually a white plastic cap, sometimes held on with a small screw.

Thanks Laurel, that makes sense

[Festive Ferg]

I would turn both thermostats up full then crank the L/S valves on the radiators in those spaces down almost closed. One turn, even half a turn is probably too much. Shut it and then listen when you open to confirm it's flowing. You should use thermometers for the temperature differential, but your chances are slim unless you can be sure it's all been designed correctly in one go...
Once you have those radiators flowing I would open the L/S valves on the furthest radiators wide. The intermediate ones somewhere between, then let the system settle down. The risk you have is that once the hot water demand cuts in you'll lose flow to the radiators so be aware of that. Is there a balancing valve fitted to the cylinder primary return?

[Piglet]

Thanks Ferg, we seem to be getting somewhere already, it's now over 20 degrees in Dad's room (which we were struggling to achieve before) and it's "only" 23 degrees in the living room! (well is was until the sun came out and super heated everything!).

Will start tweaking the L/s valves tomorrow and see how it goes.

Thanks very much for your help - I'll be back when we get a bit further with this....

The system is a bit ad hoc - it's one of those places where bits of extension and rads have been added so it's sort of evolved!