Too many rads for my boiler ?

Canucklehead

Hi

Over the years rads have been added to your system but the pipework will most likely be 15mm the result is that the pump can't circulate the water to all the rads even with it thrashing along on the 3rd speed and the system balanced to the Nth degree. You might get better results upping the flow and returns to 22mm to more of the rads.
Measure all your rads and work out the outputs from manufacturers list,and see what figure you get.
It would be worth getting a new boiler if you can, but it may not be the answer to your circulation problem.

GSR.

keystone

Whilst theres a great deal of valid stuff above this post I'd still really rather like to know whether or not the OP has got a sticky TRV problem before we all go tearing his old system out and upgrading it.

Cheers

PrivateRyan

Again, thanks for all the replies.

Only one of the rads (a recent addition) has a thermostatic valve - this is one of the 3 rads that pretty much refuse to come up to any temp. I'll check the pump tomorrow to see if it has any settings on it - from memory, it does not. I know the size of the piping is 'old' so perhaps there is an issue with trying to put that much water through small pipes. I live in a 2 story semi-detached house built in the early 70s and the boiler (space saver 38) is very old i guess.

I'm not sure whether this will mean anything to any of you - but i'm convinced that on at least 2 rads (which get very hot very quickly) ... if i turn the lockshield off, other rads in the house actually suffer not benefit. Strange ?

Tonight, i've had most of the lockshields OFF or open a little bit on the rads that are working fine - in the hope of getting some heat to the famous 3 rads which are fully open, didn't work though. The boiler is on FULL and it is quiet most of the evening - firing up occasionally.

I'll try to work out the BTUs also tomorrow - can someone confirm that the boiler is rated for 40k BTUs ? I googled it, and couldn't find the answer immediately but think i found a site in the end.

Baby on way in 4 weeks so really hoping to get something sorted by then. As i said earlier, plumber is away until early Jan and i'd love to save myself a fee if this is something i can sort myself (which would be unusual for me!).

Thanks all .....

PrivateRyan

ok - the pump. It's a Grundfos type UPS 15-50. It has a switch on the left hand side and there are three settings on it. Only one appears to work - the other two positions send the pump quiet (although i didn't wait very long before switching back!).

In the middle, there is a large silver coloured coin/disk with a slot in it .... looks like it can be turned with a screwdriver ?!?!

I'm gonna size up the radiators later and let you know the approx. BTU i get to ...

PrivateRyan

Just found an instruction manual online for the pump ... i wont be turning the disk now ....

keystone

PrivateRyan wrote: »

Only one of the rads (a recent addition) has a thermostatic valve - this is one of the 3 rads that pretty much refuse to come up to any temp.

If you take the head off does thecentral pin move up and down easily? Its spring loaded so you'll need to push hard to get it to go down but it should come back up of its own accord. Does the rad heat up with the head off?

I know the size of the piping is 'old' so perhaps there is an issue with trying to put that much water through small pipes.

I'm not sure what you mean by "small". If its 10mm microbore then we may have identified a major part of the problem. What size pipework are we talking about?

I live in a 2 story semi-detached house built in the early 70s and the boiler (space saver 38) is very old i guess.

I cannot think of why a 2 floor semi would require 11 rads TBH.

I'm not sure whether this will mean anything to any of you - but i'm convinced that on at least 2 rads (which get very hot very quickly) ... if i turn the lockshield off, other rads in the house actually suffer not benefit. Strange ?

Not if the circulation isn't correct.

Tonight, i've had most of the lockshields OFF or open a little bit on the rads that are working fine - in the hope of getting some heat to the famous 3 rads which are fully open, didn't work though. The boiler is on FULL and it is quiet most of the evening - firing up occasionally.

You really shouldn't (IMHO anyway) be trying to turn rads on or off using the LSV - once the system is balanced they should be set and whats most likely to happen is that your wrecked whatever balance your system had by altering the LSVs. Yes I do know you were advised to do this.

I'll try to work out the BTUs also tomorrow - can someone confirm that the boiler is rated for 40k BTUs ? I googled it, and couldn't find the answer immediately but think i found a site in the end.

Thats prolly not too relevant. It maybe that this boiler was rated for 40k when it was first manufactured. Its output now will be reduced - but thats NOT a reason to scrap it. Older boilers can be actually more reliable.

Baby on way in 4 weeks so really hoping to get something sorted by then.

Not a bad plan.

As i said earlier, plumber is away until early Jan and i'd love to save myself a fee if this is something i can sort myself (which would be unusual for me!).

The you should ensure that you carefully write down everything you do so he has a baseline to work from.


Cheers

keystone

PrivateRyan wrote: »

ok - the pump. It's a Grundfos type UPS 15-50. It has a switch on the left hand side and there are three settings on it. Only one appears to work - the other two positions send the pump quiet (although i didn't wait very long before switching back!).

The switch has a built in "off" period. Switch from 1 to 2 and the pump will go off then restart at the higher speed. Give it a chance. What speed was it set to? What speed does it work on?

In the middle, there is a large silver coloured coin/disk with a slot in it .... looks like it can be turned with a screwdriver ?!?!

Yes its to allow you to bleed air out of the beastie. Undoing it will allow air our and (proll) a bit of water as well.

I'm gonna size up the radiators later and let you know the approx. BTU i get to ...

You can't necessarily calculate the BTU of a rad by its physical size.

Cheers

keystone

PrivateRyan wrote: »

Just found an instruction manual online for the pump ... i wont be turning the disk now ....

Spoilsport.

Cheers

PrivateRyan

Totalled up the BTUs for the rads. I get 50,156 BTUs without any consideration for the hot water requirements. The last rad we fitted was 8000 BTU which might be the issue then ... if my boiler is indeed 40k ? Thing is - why doesn't switching it off (+a couple others) make much difference ? :-(

keystone

PrivateRyan wrote: »

Totalled up the BTUs for the rads. I get 50,156 BTUs without any consideration for the hot water requirements. The last rad we fitted was 8000 BTU which might be the issue then ... if my boiler is indeed 40k ? Thing is - why doesn't switching it off (+a couple others) make much difference ? :-(

Sorry but I'm going to ask you to park this one for a moment. Questions about the rad with the trv, pipe sizes and your circulating pump are above. One thing at a time.

Cheers