Furthest radiators poor performance

[doitall]

Just turn all the lockshield valves down a 1/4 turn at a time until they are all the same temperature.

 

[rebelbuttmunch]

All rads are hot or very hot except for the two troublesome ones. Neither of these have even a warm inlet pipe.

If you think of the rads as rungs on the ladder with the boiler connected to the two sides, where do the troublesome rads occur up the ladder? Are they the top two rungs or nearer the bottom?
How many rads do you have?

I cant quite picture the boiler in that way.Perhaps it would be connected to the two sides at the bottom? In that case these rads are the top rungs.

I've 8 Rads. Weirdly (ask the builder) the heat is going to the new downstairs rads, then upstairs, then back down to the last two rads.

 

[D_Hailsham]

I cant quite picture the boiler in that way.Perhaps it would be connected to the two sides at the bottom?

My fault , I should have said the boiler was connected at the bottom

In that case these rads are the top rungs. I've 8 Rads. Weirdly (ask the builder) the heat is going to the new downstairs rads, then upstairs, then back down to the last two rads.

Probably easier to pipe it that way. Eight rads is not a lot and should easily be handled by a 15/50 pump. What pump do you have and what setting is it on?

It's almost definitely a balance problem. Correct procedure is Here

 

[rebelbuttmunch]

I cant quite picture the boiler in that way.Perhaps it would be connected to the two sides at the bottom?

My fault , I should have said the boiler was connected at the bottom

In that case these rads are the top rungs. I've 8 Rads. Weirdly (ask the builder) the heat is going to the new downstairs rads, then upstairs, then back down to the last two rads.

Probably easier to pipe it that way. Eight rads is not a lot and should easily be handled by a 15/50 pump. What pump do you have and what setting is it on?

It's almost definitely a balance problem. Correct procedure is Here

Sorry, its 9 rads. I forgot the utility room.
The pump. If Im reading the right numbers its a grundfos ups 18/45 and its on the highest setting

 

[doitall]

What the hecks an ups18/45.

Are you sure thats not a domestic hot water circulator.

 

[rebelbuttmunch]

It looks nearly the same as this

 

[doitall]

Perhaps it's an Irish pump, never heard of it this side of the water.

 

[rebelbuttmunch]

Ive had a look at the grundfoss website and while I do see a large selection of UPS pumps, I dont see an 18/45. I know my pump is more than 10 years old, prehaps they dont make them any more.

 

[glasgowgas]

is it red in colour (same as pic) or is it yellow?

 

[rebelbuttmunch]

Red, but with a silver disc on front, unlike the pic's black disc.

 

[D_Hailsham]

Can you post a pic of the data label on the front of the pump?

 

[rebelbuttmunch]

First time to upload a pic, fingers crossed. View media item 15738

 

[D_Hailsham]

First time to upload a pic, fingers crossed.

Wot, no flash

It looks like a very old model. The current versions are the Selectric 15-50 and the Super Selectric 15-60.

15, 18 in your case, is the size of the entry port in the valve. This is not the same as the connector size or the pipe connected to the pump.

50 and 60, or 45 in your case, is the maximum head.

Your pump may be undersized now you have two extra rads.

The 15-50 works in the majority of cases and as you only have 9 rads it should be OK. In any case it is cheaper than the 15-60.

 

[MANDATE]

I experienced similar problem few months back.
Spent time removing and cleaning radiator, put it all back and the result was. Radiator still cold while others hot.
Then found by-pass valve which was fully open, closed it to almost closed and radiator got warm while others still hot.
Removed pump for examination. Inlet and outlet orifaces reduced to about 7 or 8mm with sediment build up, normally in the region of 20mm.
Decided to replace pump and the isolation valves. Radiator now as hot as others.

 

[rebelbuttmunch]

Well this is gonna sound unbelievable but I was out with my kids on our bikes yesterday cycling through a park and in the grass beside the footpath was a 25/50 pump.

Today I stuck some power into it and it whirred to life. It seems in good nick, a tiny bit of rust around the out/inlets. It doesn't look like something that has been leaking or kicked around the park. I'm going to try and connect it to the system and see if its any better than my old 18/45.