Does anyone know offhand if an old Mexico RS80 cast iron lump can be run with a sealed system? The Ideal web site does not seem to have a manual for this specific model, although it does for later versions...
Almost certainly not. There is likely no overheat stat. Also even boilers like Potterton Profiles which _probably_ could be used in sealed systems are not certified for such use.
I am sure you are right that is does not have the overheat stat, although I noticed in the manuals for the later versions, that they claimed you could get an overheat stat as an add on kit, and did explicity describe sealed operation.
For example, section 5:
If it is unsuitable, and modern versions of that boiler certainly are not suitable, there is still a way around it. One reason to do so might be to keep a perfectly working boiler in action (which is probably environmentally sound if you take into account the environmental cost of a new boiler) whilst requiring radiators above cold tank level in a loft conversion.
Basically, to convert, take the vented output from the boiler and put it straight into a plate heat exchanger of the type used in heat banks. A 14 plate 100kW should be more than adequete.
Then, the radiator system is plumbed on the other side of the exchanger with its own pump and controls (S-Plan or Y-Plan). It also has its own filling loop, pressure relief, gauge and expansion vessel. The "call for heat" output from that drives its own pump and the boiler (+ its pump).
Cost would be around 150 quid (for pump, exchanger and sealed system kit) plus sundries.
Christian.
Ring their tech dept. The older boilers certainly were not for sealed systems. They are crap so ditch it anyway.
The reason for the question was that there are issues with the header tank, and hence its owner would not mind loosing it, since the tank is installed in an almost inacesable location.
The later versions of the boiler will run on a sealed system it seems, hence I thought it worth asking the question.
I probably will to make sure...
Can't see the point of that, AIUI it has worked faultlessly for years and does everything required of it. Replacement prior to it being necessary would not be either cost effective, or environmentally sound.
Despite Eds caution I would suggest an approach to Ideal Boilers might be your best avenue of enquiry. If the manufacturers catalogue an overheat stat kit for this boiler then the result could be positive. I'm fairly sure I've run across the Mexico on a sealed system in the past and certainly it being cast iron should not preclude it since the Classic with the same pattern of heat exchanger is OK. Of course its efficiency will not be as high as a Condenser which goes without saying (not that that will stop "him" though) but any pipe mods you do now should be usable with a new boiler later. HTH
John
Thought you meant the old Mk1 Escort for a minute :-)
but not.
Somehow "80" does not have the same ring as "Cosworth" or "2000" though does it ;-)
Nope. Though the Mexico's went on for years until the rust got them whereas Cossies lunched themselves all too often provided they hadn't been nicked in the meantime.
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