Replacing Ariston A/23 MFFI combi Wilo Gold 50v help

[thewoza]

Hi all.

We have an Ariston Eurocombi A/23 MFFI with a Wilo Gold 50v pump.

We have added a lot of pipework and several more radiators to the system and now the temperature difference across the inlet and outlet on the boiler is nearly 20C (and some of the rads at the end of the run struggle to get fully hot).

Having done my research I believe the pump isn't powerful enough with the increased pipework so I want to replace the pump. Here comes the bit I am struggling with.

The connections on this pump are 1" (or 1 1/4") but all new models of pump have 1 1/2" connections. Fit a pump adapter I hear you say, but the space in the boiler is pretty limited and I'm not sure there is enough room to do this.

Any advice greatly appreciated.

Thanks

 

[mysteryman]

The pump body has the auto air vent on it, so you can't change the complete pump. You may find a more powerful Wilo pump motor which will fit the body.

Try removing the pump to ensure that the impellor is not clagged up with debris. Boiler manufacturers usually provide a pump good enough for the job.

 

[thewoza]

Thanks for the reply. Have had the pump out and everything is clean and clear. The pump is getting old now and as I say, we have added a lot of pipework (this is fitted in a commercial building, not a domestic home) so I don't think it's powerful enough any more.

Replacing the boiler isn't an option as it's a rented property (and the landlord won't put his hand in his pockets!).

So I can't replace the entire pump because of the air vent? There must be some alternative...

 

[ChrisR]

Prsumably you have an expectation of functioning heating?
Give the landlord a time limit, and that you're then going to get it repaired and deduct the sum from the rent.

It surely not up to you to play about with his boiler?

 

[thewoza]

The heating works - with the original pipework - just fine so unfortunately that isn't an option.

This isn't about getting the landlord to replace though, it's about me replacing the pump for a more powerful one...

 

[ChrisR]

Just replace the pump with a new manufacturer's part then, they wear and slow down with age.
If you can't tell if it's worn/slow or not, call a boiler man who can, and will probably find room for improvement in your system.
Nobody is going to tell you to fit non-approved parts to a boiler, and it's almost certainly not necessary.

 

[thewoza]

Thanks. So there is no way to fit a more powerful pump?

 

[ChrisR]

Not unless Ariston say so. I'd lay a tenner to a quid the problem is not the power of the (new) pump.
CHecked the pump rpm? I carry a tacho and can look it up, look for blockages, know what a worn impeller looks like, listen to the boiler, note how quickly heat gets out by feeling pipes compared with experience, check the length of the pipes with resistance charts to find out your head loss and add that to the boiler loss, and probably come back to the pump.
There is a larger Ariston of the same model, so they might say you could fit the pump for that.
If the bypass is stuck open you'd be wasting your money of course.


No tacho? No idea about the bypass?? Oh dear - better get a man in.

You haven't checked the gas rate either, I bet.

 

[thewoza]

No need to get sarcastic or try to be clever. I'm only asking for advice. But thank you for taking the time to reply anyway.

 

[thewoza]

Managed to find what the replacement pump part number was and get hold of one. Is a Grundfos 15-60 pump and it has a 3 speed setting and the auto air vent built in.

Setting 2 was equivalent to the old Wilo pump but with it on setting 3 all problems are sorted. Everything heats up quicker and gets hotter so happy with that.

If anyone stumbles across this thread the part number is 996613 which replaces 997150 & 997151 from the a23 MFFI & a27 MFFI.