Donate to Remove ads

Got a credit card? use our Credit Card & Finance Calculators

Thanks to johnstevens77,Bhoddhisatva,scotia,Anonymous,Cornytiv34, for Donating to support the site

Mira Gem 88 and combi boiler

Does what it says on the tin
kiloran
Lemon Quarter
Posts: 4092
Joined: November 4th, 2016, 9:24 am
Has thanked: 3234 times
Been thanked: 2827 times

Mira Gem 88 and combi boiler

#160563

Postby kiloran » August 19th, 2018, 12:01 pm

Our main bathroom has developed a leak in the shower enclosure, so we planned to use the second, little-used bathroom which has has a Gem 88 mixer control. Like this: https://i.ytimg.com/vi/hCsltn3RpKg/maxresdefault.jpg

Then I found that the flow control was stuck. While reading through the installation manual, I noticed a comment that the mixer valve should not be used with a combi boiler. Ours does use the combi.

I managed to dismantle the valve and with a combination of brute force, ignorance and not a little luck, the flow control is now free, and the shower is working fine. But I am intrigued.... why should I not use a combi boiler to feed the mixer?

--kiloran

Itsallaguess
Lemon Half
Posts: 9129
Joined: November 4th, 2016, 1:16 pm
Has thanked: 4140 times
Been thanked: 10023 times

Re: Mira Gem 88 and combi boiler

#160566

Postby Itsallaguess » August 19th, 2018, 12:15 pm

kiloran wrote:
I managed to dismantle the valve and with a combination of brute force, ignorance and not a little luck, the flow control is now free, and the shower is working fine. But I am intrigued.... why should I not use a combi boiler to feed the mixer?


There's a post here (last post on Page 1), with the following note from Mira technical support regarding your specific shower, and the reasoning behind not using it with a combi-system -

"Additionally, the Mira Gem 88 is only compatible with pressure-balanced plumbing systems (i.e. gravity, pumped, unvented). As a pressure imbalance between hot and cold supplies from a combination boiler will be evident, we cannot guarantee that this shower valve would produce a stable blend temperature. A pressure imbalance would also cause the seals within the shower valve to lift so you would therefore experience a leak. "

https://community.screwfix.com/threads/ ... mbi.79344/

Cheers,

Itsallaguess

kiloran
Lemon Quarter
Posts: 4092
Joined: November 4th, 2016, 9:24 am
Has thanked: 3234 times
Been thanked: 2827 times

Re: Mira Gem 88 and combi boiler

#160621

Postby kiloran » August 19th, 2018, 5:01 pm

Thanks for that link IAAG.
Does sound a bit odd to me, I would have thought that the hot and cold would be pretty well balanced since they both feed from the cold water main.
Maybe a problem if another tap is turned on or a loo is flushed, but I would have thought that would have a more or less equal effect on hot and cold.

Anyway, the shower will only be in use for the next day or two while I replace some silicone sealant on the main shower.

--kiloran


Return to “Building and DIY”

Who is online

Users browsing this forum: No registered users and 13 guests