I have just removed an old radiator to decorate and decided that we are better off with a new radiator altogether as the old one is showing signs of rust on the rear.
The one I removed is 700x1600mm single rad with no fins(convectors) and a round top. The only problem is that I have no idea what the heat output of the old radiator is and "senior management" would like it replaced with a new one with a grill top, and preferably something a little warmer as it can be a little slow to heat the room. I have had a go with "heatloss manager" and assuming my data is correct, it says that the required emitter output is
2110W.
So does anyone know what the likely output of the old radiator is, and what would you recommend I replace it with? Also where can I buy the new radiator from? Oh yes and do I need to buy anything else with it eg pipe fittings? I do not need a TRV as it will be in the same room as the t/stat.
If you look at the Myson web site, in their Premier HE range (the basic product), the nearest they make in that to your existing radiator size is one of 690mm x 1556mm. This has a nominal output of 1392W. The next one up is 1759 wide with a nominal output of
1574W. Given the sizing differences etc. it would be reasonable to say that your existing one has an output of 1400W nominal.
This is not the real output, however. The nominal figures are for a test temperature that is higher than that used in the UK. If your heating system is a conventional one, then the boiler has nominal flow and return temperatures of 82 and 70 degrees. The result of this is that the output is lower and you have to multiply the nominal figures by 0.89. Thus your existing radiator has a real output in the region of 1250W. These are all figures for single panel, no fin radiators.
Given that the room is not warming well, then 2110W from your calculation is not unreasonable as a potential requirement. If you really want to go for that output, you will need a radiator of nominal output 2370W. It's this figure that you pick from the main data sheet for the radiator.
So, let's look at Myson's Select product which is a grill top as an example. Obviously you can pick what you like. You could go for a double panel with grille Compact model of 500mm high and 1600mm wide (fits same width) and have a nominal output of
2246W or a 600mm high one and have an output of 2618W.
Do bear one thing in mind though. If this is the room with the thermostat and you heat it too quickly, you may cause the boiler to turn off before the rest of the house is warm and defeat the object of the whole exercise. If this looks like being an issue, then the option is to relocate the thermostat and put a TRV on this radiator.
It makes sense to buy new radiator wheel valve and lockshield valve. I like the Pegler Terrier ones, which are good quality and can be bought with a built in drain c*ck.
Another strategy to follow could be to put a TRV on this radiator anyway and leave it fully open if the thermostat remains in the room. If you do have a thermostat issue, you could replace the existing one with a wireless one and try it anywhere you like until you are happy with the location.
Fortunately we have a Honeywell CM67 wireless T/stat, so location of t/stat is not really an issue, and it could go in the hallway.
I think we will probably settle for a double panel single convector
600x1600. What make would you recommend and where would be the cheapest place to buy from? I will go with your recommendation for the valves
My only concern now is over the pipework. We have a sealed system combi boiler, will I have to drain down the system to fit the new valves. The radiator in question is downstairs, so there would be a considerable head of water above it?
Well, as it is a sealed system, it isn't that there is a "head of water" above it that provides the pressure, but an expansion vessel attempting to push lots of water in the system. In any case, the sealed system is easier to refill afterwards, as the high pressure blasts out the airlocks more effectively. The only problem is introducing the corrosion inhibitor whilst doing so. There are a number of methods...
I would call around the plumber's and heating merchants like Plumb Center, Travis Perkins etc.; or you can buy on line from places like Discounted Heating. Basically they just take your money and use their buying power with the large merchants so that you still get the product delivered locally. You ought to be able to get a discount at least equivalent to the VAT.
If it's an open vented system then a fair amount, a sealed system rather less.
If you haven't done it, then this is an opportunity to drain and flush the system and refill with inhibitor anyway.
only problem i see are you willing to drain the system and alter the pipes if not why dont you keep the same length of radiator and get either a single with fins or a double with fins also how much extra heat do you want do you feel that the current one is good enough but the boss would like it warmer if so a set of fins would do but if it is really bad doule panel with fins
Indeed I am relectant to alter the pipework/drain down the system, especially as it is snowing at the moment! But seriously, I had a look in Wickes today and they had a single with fins the same size as the existing radiator, price was nice but it did not have a top grille, which senior management has requested. Local plumb center has quoted £113 + vat for a Stelrad compact P+ 600x1600, looking at discount heating website it is £98 + vat. However even if I buy this, I still need to drain the system to fit the new valves. So I am dammed if I do and dammed if I dont. I guess it will have to be the Stelrad and some new valves, not sure if I should get the pushfit ones?
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