Clean pump proving pin (Baxi System 35/60)

[DarrenNewsgroup]

My Baxi system 35/60 boiler gives me the 60degree triangle error "fault on pump or low pressure" once every few weeks. I unscrew the silver part holding the microswitch, spray silicon spray over the pump proving pin, refit the silver part, turn the boiler off and on again and it works for a few more weeks. See attached photo.

I am looking for a more permanent fix. I have seen videos replacing the diaphragm and/or cleaning the pin (removing the 4 silver screws on the gold front). I think this is what I need to do next. However in all the videos that I have seen the diverter valve has been removed from the boiler to show it is cleaned /serviced. I am not sure if I can remove the 4 screws with the boiler turned off and access the rubber diaphragm / proving pin or if I need to drain the water system first.

Do I need to drain it first or will I get a flood of water if I attempt to replace/clean the parts without draining it? I have never drained a system so would probably find a boiler person to do it but if it is simply unscrewing the 4 screws, and cleaning/replacing the parts then I am certainly capable of doing that myself.

Thanks
Darren

 

[DarrenNewsgroup]

The 60degree triangle error "fault on pump or low pressure" happened again. Just reporting it here so I can keep a record of how often it fails.

A quick go on the silicone spray and it is working again, but for now long?

Does anyone know if I can replace the rubber diaphragm and /or pin without draining the system?

 

[ianmcd]

No you dont need to drain the system, you do need to drain the boiler and cover the electronics with towels, get a replacement diaghphragm they are pennies and make sure you clean the tiny waterway under the diaphragm

 

[DarrenNewsgroup]

Thanks for that clarification. I'll look into what that entails for more boiler to see whether it is something I can do or whether I really need a boiler engineer to do it.
Darren

 

[ianmcd]

It is a very simple 15 min job, but you MUST cover the electronics, some actually remove the PCB before starting, any leaking water will go straight in there

 

[DarrenNewsgroup]

Thanks Ian.

I looked on YouTube for draining my boiler and found this link

to drain a Baxi 105e. I then found this link

to replace the diaphragm. Both videos show boilers very similar to my System 35/60.

I trust the Baxi one more as it shows exactly my problem (pin not moving to hit the microswitch) and is from the manufacturer themselves. The first video shows draining the boiler from a bleed valve in the boiler whereas the Baxi video just says to turn off the cold mains inlet to the boiler and open hot taps to drain the water and then opens the diverter valve (carefully because of the spring inside). Interestingly there is no mention of covering the electronics (although I would do that as a good precaution anyway - since you mentioned it ).

I then found another video

which showed the same sort of thing as the Baxi video but also mentioned turning off the electrical power (good idea) but this did not mention opening the hot taps.

I was thinking if I followed the Baxi video (turn off cold mains inlet, open hot taps, plus turn off electric supply, plus towel over electric PCB) I would then remove the cover (taking care with the spring inside) so should be able to simply clean the pin and the inside of the cover, reassemble and see if that fixes my problem (hoping it is just a bit of gunk in the chamber that the pin moves in). At the same time I could inspect the diaphragm and if it was a bit worn order a replacement one and fit it at a later date.

As the Baxi one talks of draining the boiler I assume this means the pressure guage will drop to 0. I know how to add more water to my system (there is a valve in the airing cupboard to increase the pressure). I assume that once I turn back on the electric supply, turn on the cold mains inlet valve all I need to do is top up the pressure to normal (1.5 bar) and the job is done.

Does that sound a good plan of attack? Have I missed anything or got something wrong?

Thanks
Darren

 

[ianmcd]

I was thinking if I followed the Baxi video (turn off cold mains inlet, open hot taps

that is to change the DHW diaphragm which your bpoiler doesnt have, the diaphragm you are changing is the primary proving switch or system flow switch, not the same thing

 

[DarrenNewsgroup]

Thanks Ian for the warning.

I have looked at the Installation and Servicing Instructions manual pages 35, 36 mention "drain the primary circuit" which I assume is the bleed valve mentioned in the first video. In the manual page 5 shows "Drain Off Point" which matches the bleed valve in the first video. Page 38 shows changing the "central heating differential valve" and microswitch.

To drain do I need to turn off the cold inlet (as in the Baxi video) as well as open the bleed valve?
To refill do I then close the bleed valve, turn on the cold inlet (if turned off), then top up the pressure so the guage shows about 1.5 bar?

Thanks
Darren

 

[ianmcd]

Thanks Ian for the warning.

I have looked at the Installation and Servicing Instructions manual pages 35, 36 mention "drain the primary circuit" which I assume is the bleed valve mentioned in the first video. In the manual page 5 shows "Drain Off Point" which matches the bleed valve in the first video. Page 38 shows changing the "central heating differential valve" and microswitch.

To drain do I need to turn off the cold inlet (as in the Baxi video) as well as open the bleed valve?
To refill do I then close the bleed valve, turn on the cold inlet (if turned off), then top up the pressure so the guage shows about 1.5 bar?

Thanks
Darren

you are getting confused, the youtube poster called it a bleed valve , it isnt it is a drain point, you use that to drain the primary/system water from your boiler, the other videos are for Combi boilers yours is a system boiler not a combi boiler, you do not have a cold inlet, you may have a filling loop, not the same thing

 

[Harry Bloomfield]

As the Baxi one talks of draining the boiler I assume this means the pressure guage will drop to 0. I know how to add more water to my system (there is a valve in the airing cupboard to increase the pressure). I assume that once I turn back on the electric supply, turn on the cold mains inlet valve all I need to do is top up the pressure to normal (1.5 bar) and the job is done.

Does that sound a good plan of attack? Have I missed anything or got something wrong?

All sounds good, except there is no need to drain down, but if you drain down anyway - you would then need to add inhibitor to the CH side of the system.

Could I suggest cleaning your pin diaphragm and the rest of those parts by soaking them in a citric acid solution to dissolve the limescale? Citric acid is cheap, you can get it from many places like Wilco, Tesco etc. sold as a kettle descaler. It is just lemon juice powder.

[EDIT] I have just spotted Ian's post, by the sounds of it you do need to drain down after all.

 

[DarrenNewsgroup]

... it is a drain point... you do not have a cold inlet, you may have a filling loop, not the same thing

Thanks, so to drain so I just open the drain point and catch all water in a bucket underneath (plus rags around the area), when it stops then open the diaphragm/proving pin metal assembly (careful of spring and covering PC with rags), clean pin housing with lemon juice /descale (thanks Harry) , investigate possible diaphragm replacement. Then reassemble re-tighten drain point valve then repressurise from filling loop upstairs in the airing cupboard.

I really do appreciate you spending time helping me.

Thanks
Darren

 

[ianmcd]

Thanks, so to drain so I just open the drain point and catch all water in a bucket underneath (plus rags around the area), when it stops then open the diaphragm/proving pin metal assembly (careful of spring and covering PC with rags), clean pin housing with lemon juice /descale (thanks Harry) , investigate possible diaphragm replacement. Then reassemble re-tighten drain point valve then repressurise from filling loop upstairs in the airing cupboard.

I really do appreciate you spending time helping me.

Thanks
Darren

The most important thing to do is , when you remove the diagphragm, you will see a tiny hole in the housing, poke that with a piece of wire or something and make sure it is clear , give the pin a good scrub with pan scourer or similar

 

[DarrenNewsgroup]

I just rang Baxi to ask if the procedure is as follows...

1) connect a tube to the drain off point nipple
2) put the other end of the tube into a bucket
3) open the drain off point valve and wait for the water to go into the bucket until the pressure gauge reads zero or the water stops
4) put rags around the proving pin housing and PCB
5) undo the 6 screws on the proving pin housing
6) carefully open the cover (spring inside)
7) clean the parts with descaler
8) clean the hole the proving pin slides in
9) check the rubber diaphragm (order new one if necessary)
10) reassemble parts
11) tighten up drain off point valve
12) remove tubing
13) repressurise the system

They said they couldn't talk to me as I was not a gas safe engineer.

Is someone able to confirm that the above procedure is correct? I am having a hard time finding a YouTube video showing this. All I seem to find is Combi boiler repairs.

Thanks
Darren

 

[DarrenNewsgroup]

I had a thought...

Would it be acceptable to just try and put some descaler into the proving pin hole in-situ? I know it is not at the correct angle (horizontal rather than vertical) but I could soak some on a rag and place it next to the hole. Would it work?

Thanks
Darren

 

[Harry Bloomfield]

I had a thought...

Would it be acceptable to just try and put some descaler into the proving pin hole in-situ? I know it is not at the correct angle (horizontal rather than vertical) but I could soak some on a rag and place it next to the hole. Would it work?

Thanks
Darren

To descale a tap spout, without removal, I just wrap toilet tissue around it and give that a good soaking with citric acid. So worth a try.