After new rad fitted boiler doesn't want to switch on

[diy_massacre]

Pump running constantly probably OK.
Combined vent&cold feed as shown.
When refilling the system, open the (empty) header outlet valve first then tie up the ball cock to allow a trickle of water to flow, this helps to allow the air to vent and the water to flow through the same (combined) pipe. I have a isolating gate valve on my system so I can just crack it open to control the water to the ball cock.

Is there a vent plug in the centre of your circ pump?? you might post a picture of your pump showing the model details etc.

Hi John,

Many thanks for your reply!! First of all, attached photos one with red circle shows aerator tucked away.

Yes the pump has a drain plug, see picture and I have bleed it until water comes out. It also has a motorised switch valve to switch HW and CH. I looked up my boiler type and it has an external pump so thats the only one.

I get your slow fill solution where you tie up the ball cock to slow the water inflow, but I have a stop-cock going to the header tank so could I partially open it ( a tiny bit) to achieve the same slow rate? The tank is pretty inaccessible at the peak of the roof. I will try the slow fill idea and come back...

My boiler is on the ground floor, the pump in the attic and it switches itself off so suspect the air pocket is in the boiler loop.

Many Thanks Matt

 

[Ric2013]

Agree on using stopcock to control flow. Note that it may help to manually set the 3 port valve near the pump to the midway position for now. I suspect the problem is the pump is having to try to force air down to try to bring it back up to where it can vent to atmosphere. Pumps don't actually work well when they're up high - they need to PUSH against the water, not PULL it up. What you have is one of those badly designed systems that does this when drained. If the original installer fitted air vents, then great, but you need to find them: there's one to the left of the pump, by the way.

I'd actually be tempted to buy some new pump washers in case you need them and (with the boiler off) temporarily reverse the pump and see if that clears anything. Waiting for a gas installer to say why this might be a bad idea.

By the way, that pump will last longer is the shaft can be set to a near-horizontal position. Shouldn't be vertical!

 

[John.g]

I think those aerators are notorious as well for getting blocked but can't see any easy method of removing it short of cutting the pipework, if you wish to try filling the system very slowly, ensure boiler and circ pump off, shut that valve and drain down the whole system again, shut the drain valve then just crack open the valve until you get a trickle of water to the header tank. there is a manual vent on a bit of vertical piping adjacent to the pump, if you could remove this completely while filling but to avoid sitting along side it for a long time you might be able to attach a bit of tubing to it and put it in a bucket or whatever. Not familiar with that mid position motorized valve but you should be able to latch it in the mid position so that both the rads & cylinder coil are venting/filling together.

Also, after refilling, perhaps try pump on minimum speed or speed 2.

Incidentally, @Ric2013, those Selectrics seem to be indestructible as I have seen a number of them installed vertically and they are all > 15 years old. I think the above pump is week 40 2007, (PC:0740)

 

[diy_massacre]

Agree on using stopcock to control flow. Note that it may help to manually set the 3 port valve near the pump to the midway position for now. I suspect the problem is the pump is having to try to force air down to try to bring it back up to where it can vent to atmosphere. Pumps don't actually work well when they're up high - they need to PUSH against the water, not PULL it up. What you have is one of those badly designed systems that does this when drained. If the original installer fitted air vents, then great, but you need to find them: there's one to the left of the pump, by the way.

I'd actually be tempted to buy some new pump washers in case you need them and (with the boiler off) temporarily reverse the pump and see if that clears anything. Waiting for a gas installer to say why this might be a bad idea.

By the way, that pump will last longer is the shaft can be set to a near-horizontal position. Shouldn't be vertical!

Hi

Thanks for the response Ric

Pity its a poor design but I need to live with it at the moment. Yes I saw the vent and tried a screwdriver but it's tight, I have some WD40 on it now and will try later.

Wil also try the motorised valve at half-mast to do both heating and rads at the same time.

I like the reverse pump idea and think as long as the boiler is off is likely to clear but will try a slow-paced fill first as John suggests.

Many thanks Matt

 

[diy_massacre]

I think those aerators are notorious as well for getting blocked but can't see any easy method of removing it short of cutting the pipework, if you wish to try filling the system very slowly, ensure boiler and circ pump off, shut that valve and drain down the whole system again, shut the drain valve then just crack open the valve until you get a trickle of water to the header tank. there is a manual vent on a bit of vertical piping adjacent to the pump, if you could remove this completely while filling but to avoid sitting along side it for a long time you might be able to attach a bit of tubing to it and put it in a bucket or whatever. Not familiar with that mid position motorized valve but you should be able to latch it in the mid position so that both the rads & cylinder coil are venting/filling together.

Also, after refilling, perhaps try pump on minimum speed or speed 2.

Incidentally, @Ric2013, those Selectrics seem to be indestructible as I have seen a number of them installed vertically and they are all > 15 years old. I think the above pump is week 40 2007, (PC:0740)

Hi John

Thank you for your extensive input, much appreciated!!

I would rather not cut the aerator out just yet, also in an awkward place.

I will try the slow fill process and I like your idea of having a pipe on the open aerator manual screw, it currently has wd40 on it as it's stuck fast.

Can put the pump at 2 if that helps. I assume it was put at 3 due to the 8mm rad pipes.

Will come back later with the results.......

Many thanks Matt

 

[John.g]

Judicial (whatever that means) application of a vise grips should shift that without kinking the pipe!.

 

[diy_massacre]

Judicial (whatever that means) application of a vise grips should shift that without kinking the pipe!.

Thankyou John, it's been wd40'ed so should be better than before!

Right, I am on my way to try but just thought I would share with you the rad heating circuit piping pictures, maybe you might be able to cast some light onto this standard as I have never seen it before?

Thats 22mm to multi 8mm connectors, or alien invasion....

Many thanks Matt

 

[John.g]

No Matt,
Havn't seen/heard of that before.

 

[ShaunCorbs]

Yep standard 8 mm or 10mm spiders

 

[diy_massacre]

No Matt,
Havn't seen/heard of that before.

Hi John and earlier Ric,

Thank you for your advice, I drained the boiler component of the system this evening and slow filled the system and with a bit of gurgling its working on most of the radiators in the house which is great news. I found 5/additional bleed points ( some clagged up ) in the loft and suspect that will resolve the additional radiators and indirect tank.

My new rad and the solder joints held so all positive there too!

A BIG THANKYOU FOR ALL YOUR KNOWLEDGE, HELP AND IDEAS !! I wouldn't have solved it without you.

The very best to you both

Matt