Gas Rate 28i Jnr

[lame plumber]

apart from being a very old post, you test in service mode at max an min rates and some bolers require you to run hw to stay in the max rate mode to disipate the heat. if you dont have a service mode, hw will give you max rate heating wont for long enough.

 

[gassafe]

The Worcesters say to put in max & run hot tap, but I always find hot tap runs cold & it blasts round ch

 

[arran197]

Worcesters will diverter between mid position and CH. Always put them in max for gas rate. You're allowed a tolerance of 10% under and 5% over. So in the example above, the 26.77 kw he was getting, assuming the boiler is exactly 28kw (which they never are, they're usually about 27kw, but are badged higher), you're allowed a min of 25.2kw, so he would actually be ok to leave it as is.

 

[JBP Heating]

26.77 sounds not bad to me. Have you checked the fan pressure though? Should be a little red cap up the top near the fan.

 

[GrahamM]

This is a 2 year old post people are replying to.

The Worcesters say to put in max & run hot tap, but I always find hot tap runs cold & it blasts round ch

If the heating hits its max temp the boiler heat will divert to hot water and will not modulate down or cut off if you open tap in service mode.

 

[JBP Heating]

Ha Ha, so it is!

If the heating hits its max temp the boiler heat will divert to hot water and will not modulate down or cut off if you open tap in service mode.

Installed a 38cdi classic last week and the mi's suggest removing the diverter motor and running the hot tap when testing max rate.