warmflow

[porky2]

We Have a warmflo combi oil installed in 2008 & have had afew problems,not major, but now have major leaks on the heat exchanger due to perished seals. There is 1 thing which I would like to do whilst it is drained down & that is some sort of safeguard to switch off the boiler when the pressure drops (as per worcester, our previous) Also a probe is hanging in midair close to the control box, should that be fixed somewhere & I have been advised to install PRV at the mains set to 2bar which will prevent any further leaks, just on with that at the moment. Are ther any other mods needed for this boiler that I may as well do whilst at this stage advice would be appreciated
Tel

 

[dcawkwell]

More than likely your expansion vessel has failed and the pressure has been peaking at 3 bar causing leaks.

Very few of the oil boilers use a pressure sensor to switch the boiler off.
On oil boiler this is usually unnecessary since any air in the top of the boiler means the overheat stat is triggered. Oil boilers aren't as delicate as gas boilers.

 

[porky2]

Thanks for that info I will check it out manuana? What a great site tthis is
Tel

 

[oilhead]

You should not need to drain down to replace your leaking seals.The y will be on the secondary side of the DHW heat exchanger and turning off the mains supply will enable you to replace these seals. When replacing, use a good quality fibre washer rather than the rubber seals used by Warmflow. A pressure reducing valve will relieve some of the 'strees' on these seals, but all combis suffer from the same problem to some extent mainly because of the localised heat and aggressive water content.
Problems with pressure loss are caused by the primary side of the system, and usually from leaks around pump valves and auto air vents.

 

[porky2]

Hi oilhead thanks for that. That is useful info which I will remember next time! I needed to drain down fully because the external drain cock had split thro the frost & needed replacing& now after checking the expansion tank (thanks to dccawkwell) I need to replace that. Can I replace it with any make as long as its the same size? & if I take al lthe bits I,ve taken off the heat exchanger, incuding the mixer valve, to the plumbers merchants & ask them for fibre washers instead of rubber thats the job sorted - fantastic. We live out in the country 2mls from the nearest bus stop & since we decided to move, because of our age, everything seems to be breaking down!
Thanks again to u both
Tel

 

[dcawkwell]

Hi oilhead thanks for that. That is useful info which I will remember next time! I needed to drain down fully because the external drain cock had split thro the frost & needed replacing& now after checking the expansion tank (thanks to dccawkwell) I need to replace that. Can I replace it with any make as long as its the same size? & if I take al lthe bits I,ve taken off the heat exchanger, incuding the mixer valve, to the plumbers merchants & ask them for fibre washers instead of rubber thats the job sorted - fantastic. We live out in the country 2mls from the nearest bus stop & since we decided to move, because of our age, everything seems to be breaking down!
Thanks again to u both
Tel

Expansion vessel may only need pumping up. Or a new tyre valve.
Otherwise it might be about £50 for a new one.

 

[oilhead]

Your mixer valve is compression fittings, so if you've dismantled, a few turns of ptfe tape round the olives should reseal. An expansion vessel of the same size and connections will suffice.

 

[porky2]

I have removed the cap & pressed in the valve & dirty water has come out. Pumping it up doesn,t make any difference so it looks like its goosed.
Can u recommend a site for the tank 12ltr 320mm dia x 160thick approx
The mixer valve connections are not comp fittings, it uses like a domed rubber seal unless the rubber has distorted Hopefully I may be getting some of these on Tues fingers crossed
Tel

 

[porky2]

double checked the expansion vessel using 1 of these 12v comp & it has pumped it up to 10psi which has dropped t o about 8 over a 12hr period. I had been checking for loss of pressure over say a 4wk period & it had lost maybe 1/2 a bar. I then topped it up.. When I checked again it had risen to 3bar & was leaking round the heat exchanger. I eventually discovered the isolating valve needed to be positioned spot on to stop the water flowing, & the other thing was I hadn,t disconnected the filler hose.
Only have myself to blame for these problems I have