Baxi 105e - not modulating

[kktoday]

Shouldn't drop like that but is. Yes for sure working P at inlet. Not Burner pressure. Hence the problem.
22 mm at boiler does become 15mm behind washing machine. Someone has put in 2 feet of 22mm? Maybe this says something. Customer also now told me boiler was changed 2 years ago because of poor hot water. He was told hot water would always be poor to bathroom because it's a long run (10m?) and the pipes were badly scaled. As you say gas4you something is beginning to smell of rat.

 

[gas4you]

think you are going to have to quote for new gas connection from meter. On this size combi I never go more than 15m max equivalent length of 22mm copper straight to boiler. Get your pipe sizing chart out

 

[kktoday]

Could be fun. Converted flats.
My view is if you're running new gas pipe then why not put in 22mm.

 

[gas4you]

not that i've used it but thought about tracpipe?

 

[kktoday]

Never used it but I like the sound of it. Maybe worth considering.
I imagine it as a more rigid version of PEX - or is it more flexible?

 

[Agile]

Will report back on working pressure.
22mm gas piping to boiler - so again assumption made of sufficient flow.
It's easy to see a diagnosis when you want to. Take nothing for granted.
One of my bugbears is the difference between flow rate and pressure.

Reading your posting has reminded me of an intriguing problem I discovered today! New owner just moved in, previously top quality tenants, 21 mB at meter, 21 mb at cooker and 2.5 mB at gas valve inlet on boiler and only about 6 kW input power to boiler so OK on CH but not DHW.

The meter had about 7m of 22 mm pipe going to the boiler with about 4m of horizontal dog leg not accessible due to flooring.

Now since it must have worked until a few weeks ago, how can it have become so blocked so quickly? The valve on the boiler inlet is fine. The blockage is somewhere in that 7m of pipe after the tee off to the cooker.

Tony

 

[Slugbabydotcom]

Smacks of a job I did recently as well. See the 3rd post here

 

[ChrisR]

Had one where there was about 12mbar at the boiler, reducing every landlords cert. Turned out to be ptfe stretched across the gas inlet valve connection, the gap filling with something or other. Never actually saw it, just poked an allan key down and felt it.

 

[Agile]

My job mentioned above is very odd though.

The blockage is just in soldered 22 mm pipework between the tee to the cooker an dthe inlet valve to the boiler which I have inspected.

Its all only two years old and the filter on the gas valve inlet is totally clean!

The pipework is either exposed on under the floor where no work has been done or anything disturbed.

Tony

 

[Slugbabydotcom]

Now since it must have worked until a few weeks ago, how can it have become so blocked so quickly?

Well I cant see whats actually blocking it but heres an idea

All it takes is a vertical section of pipe to be knocked and all the copper sulphide ends up in a heap at the bottom

 

[kktoday]

update - eventually located the problem to a mass of what looks like flux at an elbow. A tarnished green blob almost an inch long almost entirely choking the pipe. I have no idea how the boiler was ever commissioned. The confusing part is the report of deteriorating hot water performance. Can only imagine the flux drying out and moving over time.