POtterton PUma 80 Low Pressure - solution help needed plz

[Biffa001]

Hi all,

I´ve had an intermittent low pressure light problem for the last years or so, say every six months or so the light will come on (then no hot water or CH ), I will top up the pressure with the tap on the side, then it takes about a day and a half for the light to go out and it all works ok again for 6 months ish.

I am guessing that my pressure switch is getting stuck after a low pressure warning which would explain the day and a half for it to right itself and the low pressure light to go off and then all is ok.

I read on this forum that I can disconnect this from the PCB to get things working again, and also to see if it really is this switch causing the prob - can you check the picture below and tell me if this is the correct plug to unplug from the PCB (according to this old post here its the one with the 2 yeloow wires- //www.diynot.com/forums/viewtopic.php?t=17314- this should be the one):

Not the best picture but you can see I have pulled forward the front panel with the switches on and you can see the bottom left of the PCB.

I now also have a second problem which I may have caused myself. Having over pressurized the system I used the red tap thing inside the boiler on the right (picture below) to drain some water out of the overflow pipe that goes outside of the house to the drain:

This now drips constantly and the pressure slowly drop over the course of about 2 hours ish from 1 bar to 0.5 bar.

If I have the correct plug (with the yellow wires, pic 1 above) to disconnect the low pressure thing and can get my boiler providing hot water again, that would be a start. I can then deal with getting a new part for that.

I believe it also looks like I will need a new part that is now leaking (picture 2), but can counter that temporarily by adding more pressure when needed just so we can shower!!

So, all I need to know is, if I unplug that plug with 2 yellow wires from the PCB, will my low pressure light go off (as the pressure is ok when I top it up)?

 

[Agile]

I think (?) that the LP SW in the Puma is a NO switch so disconnecting one wire from it should make the boiler function again. The water inlet to it is probably blocked and can sometimes be poked clear.

The flow sensor is leaking and dripping onto the pump. It might stop if you tighten it more or you may need to remove it and put some PTFE tape on the threads.


Tony

 

[Biffa001]

Wow, thanks for the speedy reply. We are already back to the olden days (well my parents days!) of filling a bath with a kettle!

I think (?) that the LP SW in the Puma is a NO switch so disconnecting one wire from it should make the boiler function again.

It´s actually more work to get to the LPSW (I think) so if the item in my picture is the right thing to disconnect to make it stop, would it be ok to do this instead as I could yank that off the PCB in about 2 secs?

The water inlet to it is probably blocked and can sometimes be poked clear.

I will need to have a good look tomorrow to find out what that is as DIY and boiler fixing is not normally my thing! I can rebuild a PC but a boiler is a tad scary!

 

[Agile]

I would advise against touching the PCB or even looking at it.

There is only one screw at top of PCB carrier and this allows the PCB carrier to hinge down to expose the LP switch.

As the boiler has an o/h stat its not a big problem to leave the LP switch dissed for a few days. Some models dont even have them fitted.

Tony

 

[Biffa001]

So to make sure I am looking at the correct item to remove a wire from - if you look at my first picture again, is it the item directly behind the PCB board (sort of below the piece of yellow/green tape in the pic)? It´s round and you can see about 4 screws on it in equal spaces around.

Thanks for the help mate, I may even get this sorted before bedtime!!

 

[Biffa001]

Just looking at the puma manual posted here - http://www.partsarena.com/baxi/System/DATA/Dx/DS1/installation/2248/I04-2248/I04-2248.htm

I can´t find a part called a ¨low pressure switch¨, but there is a:

- Air Pressure Switch
- Water Flow Switch D.H.W (which I think is the one I am talking about)
- Water Pressure Switch

Which of these would it be please?

 

[Gasguru]

This part



Clean out the port in the diverter valve, note the pin numbers on the old pressure switch (replacements often have the plastic terminal cover on the wrong pin), read the FAQ's on expansion vessels and replace the auto air vent (bound to leak afterwards if you don't)

 

[Biffa001]

Clean out the port in the diverter valve, note the pin numbers on the old pressure switch (replacements often have the plastic terminal cover on the wrong pin), read the FAQ's on expansion vessels and replace the auto air vent (bound to leak afterwards if you don't)

Thanks for the pic, as least I know which part to disconnect now!

As to the rest of what you said, you lost me after ¨Clean out....¨ ! As I said I am not anywhere near what you would even call ¨handy¨ with this sort of thing.

I will disconnect this part then report back and also do a bit more research on what you posted.

Thanks again guys for the help, it´s much appreciated

 

[Biffa001]

Right an update - I´ve unplugged one of the yellow cables attached to the part you showed in the picture and the boiler now starts up and the warning light is off - we have hot water again! My wife will be so pleased!

Also Agile mentioned earlier:

¨The water inlet to it is probably blocked and can sometimes be poked clear.¨

Is this something I can get to without taking the part off? If so, which bit is it? If not, does it involve draining the system, removing the part etc?

I´m going to keep an eye on the pressure to see if the leak is affecting this badly or not. Unfortunately there is no sticker on my part to see what it exactly is to order a new one?

Thanks guys for the continued help, much appreciated

 

[Agile]

You have to drain the boiler but not from the red knob!!!

Then you unscrew the LP switch and poke its inlet AND to exposed hole in the fixed pipework.

Wrap a little PTFE tape around the thread when refitting.

Refit the temperature sensor at the same time!

They dont always unblock so you might have to buy a replacement at about £23.

Tony