Third central heating pump in 5 years!

[Glenbirnie]

Ive been in my new (old) house about 1 year. I took out a Rayburn boiler cooker range as it had caused the previous owners trouble from day one, they left all the invoices and complaint letters, thanks for telling us after we bought the house!

It turns out they had 2 central heating pumps in about 4 years and now the current one is making a hoor of a noise.

The pump was under the floor next to the Rayburn. Weve put in an Ideal Logic condensing boiler and split the heating circuit, upstairs and downstairs with a 3 channel timer. The pump is now near the hot water tank and boiler relocated in utility room.

Im figuring that this 3rd pump is failing due to the previous system and supplier. Im hoping that when I put a new pump on now it will last as these Grundfos 15-50's should.

Our upstairs circuit is microbore at the moment which will be changed this summer. Could this be causeing the pumps to fail?

Any other reason these suppossed bomb proof pumps might be failing?

Thanks

 

[biscuit77]

What is the water quality like inside the heating circuit?, sounds like the water quality isn't up to much.

 

[doitall]

Nearly always bad installation.

My previous boiler still had the original pump at nearly 40year old.

 

[Glenbirnie]

water quality is excellent! there has been a magna clean on the system for some time, obviously fitted as a possible cause for concern. Also system had been power flushed.

My plumber wash surprised at how clean the water, header tank etc all was.

It was drained and filled again also by us when the boiler and circuits were changed.

I spoke with the previous company who used to do the plumbing for the old couple we bought the house off and asked their thoughts. They suggested it may have been a faulty batch of pumps?

 

[dcawkwell]

1. Remove Rayburn. (No place in a modern central heating system)
2. Remove all pumps (you only need 1 pump up to about 15 radiators)
3. Flush system.
4. Either keep ideal boiler until it break then replace it.
5. If not already on a sealed system do that by removing
heater tank for central heating.

Job done.

 

[Glenbirnie]

Ive read the Grundfos 15-60 130 pump has a greater head for bigger systems and restrictive systems.

I have the 15-50 130.

Could the restriction of microbore be reducing the life of the standard pump? Or is that a daft thought as they are simply the same pump produceing slightly different pressures?

Thanks

 

[biscuit77]

The rayburn has already been removed. Not likely to have been a bad batch off pumps. Does the system fill up with air all the time?, do you have to vent radiators all the time?. Might be a leak in the system or its drawing air in to the system, if the pumps are running dry they'll soon fail.

 

[Glenbirnie]

We have a a heated towel rail in the system which is the air trap. A load of air came out of it a week after the new boiler was put in as Id expect then a very small amount a few weeks later when I thought to check one day. Tried a few times since and no air at all just instant heating fluid.

Im happy there is no air leak.

Im obviously thinking its the previous system, way the system was used etc that was the problem it just seems odd.

They were running the pumps on speed 3 allways and were an old couple who had the house at 24°C all the time, £450 a month gas bills!

But still Id expect a considerable life from a Grundfos pump.

i'll stick a new one on from an independent supplier and see how it goes. There is no reason now why it shouldnt last.

My boiler keeps kicking out a fault code Fd (Ideal Logic) means no flow!

Presume the pump must be stopping or something but this would make sense if its knackered.

 

[DeltaT2]

A 15-50 should last 50 years. Who's replacing these circulation pumps, did you/they not 'clean the can' when the last one failed?

Of course the condition of the central heating system water plays a big part in the longevity of any circulation pump.
As DIA has said, system design is also a factor.

 

[doitall]

Nearly always bad installation.

Still applies, perhaps a pic showing the pump and attitude

 

[Dan Robinson]

What is the orientation of the pump?

 

[Glenbirnie]

There is no point me posting a pic as the pump which as just failed has only been on the new system since November.

I therefore put its failure down to something from the last system.

I know they had severe problems from day one with the Rayburn, heat exchanger was replaced, fan replaced, main circuit board melted and replaced etc a long list of problems and complaints. I couldnt put into words how bad the service from Rayburn/AGA had and has been on a cooker/boiler that cost the previous owner nearly £10k! They are a disgusting company and their products are poor.

The pump that has just gone was on the Rayburn system most of its time.

Youve answered my questions though these pumps should last a long time as I thought.

I will replace it and see what happens, I have a new system, clean as you can get, magnaclean filter spotless, new boiler and a lot of copper pipe replaced.

If the next one doesnt last a long time I'll be on here again for your wisdom.

Thanks to all.

 

[Glenbirnie]

the pump used to sit on its back, the big silver screw and Grundfos face palte with all the spec facing the sky.

 

[plumbplumb]

It's not the pump at fault and if the water is clear as you say there will be more than likely an issue with pipework configuration vent, feed pump position etc.

 

[Glenbirnie]

so why the pumps going then?

If the water is clean and allways been clean (I can only presume) and you are correct then it must have been an air problem, the pump running dry?

Why else would pumps fail if the water is clean, no debris etc