Pulsacoil BP120 - repair a leak advice

[astiling]

Hi all, we've a small flat with one of these in and it has a couple of small leaks but otherwise works fine.

The leaks are 1) from the drainage exit and 2) around the connection of the main heater unit .

I thought I may have a go at fixing these but wanted to check I wasn't doing this wrong.

1) drainage point - possibly this needs replacing or just tightening. I didn't have any tools when I had a look but plan to try opening and then re-tightening this to see if that is a simple fix but I guess it is a long-shot.

2) heat unit - I guess I need to empty the tank down before removing this to avoid a flood So was thinking to use drainage point and empty tank, isolate from mains, then remove the heating element assembly to check for any obvious issues. Hopefully some PTFE and re-fixing will resolve this.

3) If drainage point has failed for some reason - are these generic items that I can pick up at a plumbers' merchant? Or special supply (maybe not even available)?

Thanks for any tips
Adam

 

[Ethel H]

Can't answer your direct question but I don't think your leaking woes will end, even if you fix your current problems because the insides of the thermal store is made of corrodible copper and not stainless steel. We had a pulsacoil 2000, a vented thermal store like yours, and it was the most error prone and over complicated thing we had ever seen. It had a PCB board, flat plate heat exchanger, pump and other bits and pieces that would fail one after the other every couple of years. It was designed to fail and Gledhill must have made tons on repair call outs. And we had to remember to manually refill the overhead tank every year otherwise the whole thing would fail. The copper cylinder concealed inside ended up corroding and leaking as all copper stuff do.

In the end we replaced it with an unvented stainless steel hot water cylinder which does away with all the components I mentioned above. It is simplicity itself - fewer bits means less to go wrong, its almost maintenance free. Cost us £1300 supply and fit. Luckily the soil stack (vertical waste pipe concealed behind plasterboard) was near the cylinder so the discharge pipe from the cylinder could be cut into the stack easily. We could identify where the soil stack was by following where the kitchen sink waste pipe ended up going but we could have easily cut into the kitchen sink waste pipe itself had we not been able to locate the main soil stack.

If you do end up going unvented, you will enjoy higher water pressures too. But do not go for an Ariston cylinder, they only use copper heating elements with no option to upgrade whereas every other manufacturer uses incoloy alloy as standard with an option to upgrade to titanium that won't corrode in aggressive water areas like London.

 

[astiling]

Thanks for that. I'll give fixing the current small issues a go but before any real expense I'll get a replacement then if the tank itself is going to start causing issues going forwards not much point in putting more money into this.

 

[astiling]

OK so an update to hopefully help others in future.

I purchased: immersion wrench, PTFE liquid, new drain cock, hose, inhibitor so maybe £40

Plan was to drain down the system and remove/replace element and replace drain cock.

Isolated all electrics
Removed supply cables from element - these were in really bad shape and hard to believe the neutral was actually connected, possibly had been a loose/intermittent contact causing the plastic sheathing to melt?
Checked the heater element could be undone by loosening a little - all good
The drain cock was non-functional - disassembled and used thumb to cover while tank drained. After a short time reinserted the screw in part and that drained for 1hr+
Replaced leaking + broken drain cock using plenty of PTFE liquid
Removed element and cleaned up a little, used drill bit (by hand) to clean out the threads, cleaned up treads in female part on tank also
Re-fitted element with PTFE liquid again - done up properly tight
Left for 3 hours to dry out PTFE
Filled boiler
Filling via header tank took some time for the first 25% - many air blocks. On my system BP 120, there is a vent tube with a rad style nut at the rear top of boiler that I used to release air and left open while filling then closed
Turned back on electrics
Left overnight on timer for this morning

tadaa - hot water and no leaks Checked the air vent and released a little air - satisfying gulp from header tank.

So, all good with no dramas.

Really hope that helps someone in a similar situation to me. We had had 2 different companies out to fix the system before, replacing elements and timer. I wasn't there so have no evidence of any work aside from the new timer. Considering the leaks we had were old as the flat had a damp smell and you could see the huge water damage from just approx 100ml water leakage per day I don not think they could have actually done anything with the boiler itself - surely if the draincock was broken they would have replaced that and mentioned it! Of course maybe this all went wrong coincidentally after they had been.......

Much happier now!