I have a combi boiler that appears to be functioning properly save for one thing. The hot water (DHW) is not getting as hot as it should be.
If I measure the gas flow at the mains I see it uses:
81 cubic feet per minute on both central heating (CH) and DHW.
According to the spec, CH should be consuming 90, and DHW 120 cu.ft/min.
The gas pipe starts out as 1 inch, and ends up as 7/8" where it enters the boiler. Somewhere hidden in between, it changes.
I read that even 3/4" pipes should allow 120 cu.ft /min to flow through up to 30 feet of pipe, so I am of the opinion that the pipework is fat enough.
Where should I look next for the blockage? I am wondering if the mains supply is itself inadequate, or if the gas control valve is strangling the supply or perhaps an injector is partially blocked.
Thoughts welcome.
If I measure the gas flow at the mains I see it uses:
81 cubic feet per minute on both central heating (CH) and DHW.
According to the spec, CH should be consuming 90, and DHW 120 cu.ft/min.
The gas pipe starts out as 1 inch, and ends up as 7/8" where it enters the boiler. Somewhere hidden in between, it changes.
I read that even 3/4" pipes should allow 120 cu.ft /min to flow through up to 30 feet of pipe, so I am of the opinion that the pipework is fat enough.
Where should I look next for the blockage? I am wondering if the mains supply is itself inadequate, or if the gas control valve is strangling the supply or perhaps an injector is partially blocked.
Thoughts welcome.
