Faulty pump?

[bolst3r]

Last week my boiler wouldn't start. Bit the bullet and signed up to Baxi repair and support but on inital inspection the guy said there was an airlock in the system which was turning the boiler off. He bypassed the switch to get it running thus proving the boiler was fine.

I ran the system for a couple of hours and bled the radiators. The room thermostat turned the heating off but later it wouldn't come on again. I could hear the relays in the thermostat and programmer click, MV move and water starting to be drawn into the boiler but it wouldn't fire. It seems to constantly draw water but not fire so I killed the power to prevent issues and used the immersion.

A few days later I decided to have another look at it, I poked my finger in the header tank feed pipe, bled the pump and vented it. I also turned the pump motor down to setting two and back up to three and the boiler fired back up - yay!

I then turned all the rads in the house up to full and spent the next four hours removing lots of air from the system. After this point it seemed to come on/off as normal but the next day it stuck again, this time I hit the pump (lightly) with a screwdriver and turned the motor down to two and then back up to three and it started again.

From this point it has been fine however a fuse has been tripped in the house this morning which is very unusal.

So my question is, do pumps start to exhibit these issues when they begin to fail, is tripping a fuse common if the motor starts to overwork, gets stuck etc.?

Initally my plumber felt if all the rads in the house were heating up the pump is working correctly but it seems strange a fuse has now gone.

 

[durhamplumber]

question is, do pumps start to exhibit these issues when they begin to fail, is tripping a fuse common if the motor starts to overwork, gets stuck etc.?

In general,pumps do not ""nuisance trip"" fuses much.They either work or not...Modes of failure..1.Water ingress causes a short and blows fuse.2.Seizes up from crap in impeller or bearings seize.3.Capacitor goes.If bearings are going they sound rough.If capacitor goes,fuse blows.Which Baxi is it?

 

[bolst3r]

It's a Potterton Promax SL (30 I think)

The boiler guy said he tested it and nothing was wrong, used a magnet (I seem to remember) to test a switch connected with an airlock, also ran his multi-meter across it and said look it's reading correctly, if I bypass it the boiler will start – which it did.

He said there was likely a large build-up of air in the system and suggested putting in a new bigger pump in, which would help to push the excess air out, as this had caused it to shut down.

So once he left I tried to bleed the system but not much came out. Subsequently i've managed to remove quite a bit and now all the radiators are getting hot.

I had noticed over the last few months that the system had got really loud due to gurgling but stupidly didn't put the heating on and bleed the system. Since i've gone through this process it is as quiet as it has ever been.

I don't know if this tripped fuse is just a coincidence or something pump related as i'm still trying to gauge if the issue is resolved or not.