Mira 415 Compatibility: Glow worm Express 80 Combi Boiler


28 Jun 2006
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United Kingdom
Please help!

I've tried to contact Glow Worm Technical support but their telephone que is never ending and nobody appears to reply to technical support emails!

I've got a Glow worm Express 80 Combi boiler and i'm looking to install a Mira Combiforce 415 EV Mixer Shower. However, Mira tell me that the shower will only work on: 1) A high-pressure system 2) A Fully-modulating boiler

Could anyone tell me if the Glow worm Express 80 combi boilers are fully-modulating and work well with the shower i'm looking to fit?

Has anyone fitted it on the same boiler- does it work? Any problems?

Your help, advice and experiences would be appreciated.

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The boiler is fully modulating and should be compatable with the Mira shower. The boiler is old but should still cope if it is in good condition.
cheers mate- i really appreciate the quick reply.

with regards to it also needing to be a high pressure system- does my boiler fit that requirement too? (Sorry if my questions sound a little bit silly, it's just that i'm only just getting to grips with plumbing!)

thanks again,


p.s. How do know that the boiler is fully modulating- have you worked on one before? The reason i ask is that i had a corgi plumber come out to check the boiler, and he couldn't seem to tell whether it was fully modulating or not!
There is a difference between a plumber and a boiler engineer!

One should add that as well as being fully modulating by design the boiler and particularly the gas valve should be properly set up.

I once went to a boiler and the gas valve minimum and maximum settings were the same so there was no modulation and the hot water went hot-cold, cold-hot !

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I used to work for Glow-worm. Your boiler hot water works off mains water pressure which will be higher than if it is tank fed where a different type of shower would be required.
A gravity fed system can be high pressure - if a tank is 25m high you will have 2.5bar pressure, a main could be as low as 1bar- so a tank fed system in some case can be classed as high pressure and provide more pressure than an in coming main. Anyone know what figure is classed as high pressure?

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