Hi, my first post to a group - please can anyone help with the following:
I have a Worcester multipoint boiler (fitted about a year ago to replace a very similar looking Main Severn multipoint boiler) upstairs in the bathroom. It supplies a wash basin and bath upstairs and a kitchen sink and washing machine downstairs.
I am having central heating installed based around an Ideal Isar HE24 condensing combination boiler fitted in the bathroom, supplying 7 radiators and DHW. The installation of this is almost complete with just the connections for gas and water to the boiler and its hot water outlets to be connected. The plumber is planning to disconnect the multipoint boiler and divert its gas supply and water feed to the new boiler and to connect the new boiler's DHW feed to the point that the multipoint currently supplies.
I am wondering if I could keep the multipoint boiler in use to feed the washing machine and probably the downstairs sink (and later, a yet to be fitted, downstairs wash hand basin) and so have the new combi boiler supply just the upstairs bath and wash basin (and later, a yet to be installed, shower).
The reason I am considering this is that I would like DHW upstairs (particularly to a shower), not to have its flow rate or temperature unduly influenced by either the washing machine requiring hot water or hot water being used at the downstairs sink.
Is my idea workable? I realise that the cold water supply might be an issue that could effect hot water flow rate/temperature if it is not of sufficient pressure but I have no idea how to judge this. Also the main gas supply may not be able to feed enough gas to maintain both boilers at full capacity; again I don't know how to judge this. The new boiler is supplied with gas via 22mm pipe all the way and the multipoint has 22mm to it except for the last 2 meters which is 15mm - this could be changed to 22mm all the way.
So, is my idea workable, effective or overkill that would have problems that I haven't seen?
In case these figures help: The multipoint has a max rated output of 21.4 kW with 4 to 12 litres/ min flow for a 25 degree temperature rise (control set to minimum) and
2 to 6.1 litres per minute flow for a 50 degree rise (control set to maximum).The Isar HE24 has max DHW output of 23.4 kW (80 000 Btu/hour) with 9.6 litres per minute for a 35 degree temperature rise. DHW Specific rate
11.2 litres per minute (whatever that means).One other problem, it's now Sunday 11th March 2007 and the plumber is coming on Monday to finish the installation and (maybe), remove the multipoint boiler.
Any advice would be very helpful and most welcome.
Regards, Steve.