Radiator Frequenty Asked Questions

Cast iron radiators: Some of the questions we are commonly asked.

How do I know what size of radiator I require for my room?

Calculations for room heat requirements can be quite difficult; however we have a programme which can work out what your requirements are in British Thermal Units (BTU) or Kilo watts (Kw). Once you have worked out what heat out puts you require OR size of radiator, please look at our styles and sizes to match which radiators are the most compatible or let us have your requirements to quote a competitive price for you. (If you are unsure, we would always recommend that a final check is made on this calculation by your heating installer prior to order).

Why are our longest standard radiators approx 1.2m long?

There are two main reasons why our longest radiators are approx 1.2 metres long. Firstly, as we sell our cast iron radiators all over the UK, Eire & Mainland Europe, in order to keep shipping costs to an absolute minimum we use a standard size pallet, which is 1.0m x 1.2m in size. Anything larger incurs an additional pallet cost and delivery prices. Secondly and just as important, is the actual weight of the radiator and how it is handled upon delivery. Obviously cast iron radiators are heavy and our 760mm x 19 sections weighs approx 100kg. So this needs to be considered. At no extra cost,we can supply longer bespoke cast radiators, so please call us to discuss options available.

Are cast iron radiators more heat efficient than modern steel radiators?

Yes, although they may take a little longer to get to full operating temperature (though on any sound heating system this time should be negligible) cast iron radiators are highly efficient, with darker colours being the most efficient conducting colour and due to the ability of cast iron to retain and spread heat evenly for much longer periods than steel, even when your heating has been switched off.

Can you paint my radiator?

Yes, we do offer a spray paint service for all radiators we supply for you for a modest fee in our professional spray booth.

Can I paint my own radiators or get someone else to paint them?

Yes, you can arrange to paint your own radiators or we can deliver the radiators to a nominated paint shop of your choice if required. The primer we use is a cellulose based primer and so it is alright to use other cellulose based paints. (We do not recommend powder coat finish as this will affect the section seal/gaskets when put in finishing oven causing your radiator to leak).

What size pipe work is required?

Our radiators are prepared to accept ½” BSP. The diameter of the pipe work required to supply your cast iron radiators will be determined by the systems supply requirement, but all can be adapted by copper-brass converters, available from most plumber’s merchants, by your plumber.

Who can install cast iron radiators?

Our radiators should be installed by a qualified heating engineer or plumber. They are compatible with all modern pipe work systems & come with 15mm (1/2”) bushes - connections as standard.

Can I use your cast iron radiators with my existing heating system?

All of our cast iron radiators are compatible with normal central heating systems, and come complete with ½” British Standard fitting connections. This means you can change as many or as few radiators as you wish.

Can I use small/micro bore (10mm) or larger (22mm) pipe work?

Our radiators can be used with existing pipe work which is either narrower (10mm) or wider (22mm / ¾”). It is quite possible and simple to use small bore/micro bore pipe work. Copper/brass Converters or Reducer fittings are freely available at little cost to enable the radiator to be fitted to smaller (10mm) or larger (22mm) pipe work. On larger radiators (those in excess of 3000 Watts) it may prove a problem in balancing the system, so please consult your plumber for further information. However, we always suggest speaking to your heating engineer or plumber to make sure your system is compatible.

Where should I position cast iron radiators?

This really is up to you, however, traditionally, radiators were in the coldest part of the property. This would normally be on an outside wall or under a window; however it is perfectly acceptable to position your radiator to suit your rooms’ layout taking into account windows, doors etc. For larger rooms, it may be more beneficial to have more than one radiator to give an even heat spread for the whole area.

What valves should I use for my radiator?

You can use either a Thermostatic or Manual valve set. On larger radiators, or rooms where the radiators have been oversized we would normally recommend the fitting of a TRV (Thermostatic valve) although this is not essential. Our radiators are designed to accept both valves at the bottom for pressurised systems or if required for gravity fed systems, with the inlet valve fitted to the top right hand side and outlet (lock shield) to the opposite bottom left hand side. One point to remember is that if you have positioning a radiator in the same room/area where there is a central heating thermostat, you should only use a manual control valve set. This will prevent the thermostat & a TRV valve counter acting each other.

What is the difference between a TRV (Thermostatic Radiator Valve) and a Manual one?

A TRV controls the room temperature, by sensing the air temperature and automatically opening and closing the flow to the radiator. A manual valve can only control the temperature of the radiator regardless of the room temperature & is usually controlled via a room or general thermostat.

How are valves fitted and cast iron radiators sealed?

It is important with our cast iron radiators that no caustic plumbing compounds are used on any part of the radiator, its valves or connections (this can react with the iron, breaking down the sealing washers in both the radiator & any ‘O’ rings in your boiler or pumps). If any compounds are used then you must return the water to Ph neutral before operating the system. All radiator joints should be dry jointed, with PTFE tape wrapped around the valve threads for tightening. We would recommend the use of a thicker gas type PTFE tape on parallel threaded valves.

I see that many of your TRV valves offer a 'Frost Protection'. What does this mean??

'Frost Protection' valves offer exactly that, protection for your heating system from the effects of frost. Most of our TRV (thermostatic) cast iron radiator valves offer this and will therefore, continue to work when in the fully turned off position when the temperature in the heating system (water temp) drops to around 6 or 7 degrees. This is to ensure that if, you are away and your have turned all your valves to the fully wound in - Off position and the temperature drops to the levels above, the valves will automatically open to help prevent the heating system from freezing and causing damage. Obviously, your heating needs to be on and operating for this to work. In view of this protection, please remember that the valves may not fully shut off when in the fully wound in - Off position, so installing an inexpensive in-line isoltaion valve may be helpful when plumbing in your radiators.

Is it safe to use Inhibitors or other plumbing compounds?

Ph neutral inhibitors are fine to use, but NO caustic/corrosive/acidic plumbing compounds or liquids are to be used on or in any part of our radiators, our valves or connections and that if aggressive flushing agents are used, the water in the system MUST BE neutralised correctly following their use appropriate crystals or similar. Where caustic and/or corrosive compounds (liquid or other) have been introduced into the radiator(s) which have caused damage to seals/gaskets, this will invalidate any guarantee offered.

I see that you do lots of standard sizes, but what if I need a different size to what is offered?

After many years and 1000’s of radiator sales, we have established what the main size radiators our customers want and so we have all our radiators supplied pre-assembled and tested in the sizes shown on our site. However, we can make each radiator larger or smaller within reason, depending on weight and dimensions, but this may add to the lead-time for preparation due to the time to split an existing radiator, make to size required, re-pressure test and re-prime each radiator. We ONLY charge pro-rata on the number of sections used. Please call or email to discuss your requirements further to to confirm prices for this service.

Do I need a wall stay for my cast iron radiators?

We always recommend that you fit a wall stay with our cast iron radiators. These will help stop the radiator being moved and thus moving the pipe work into your valves which may then subsequently leak. As a general rule we suggest 1 stay for cast iron radiators up to 10 sections long (for the traditional 460mm range 1 stay for up to 19 sections will be fine) and 2 stays for cast iron radiators 11 - 19 sections long. We can supply stays for both solid-block walls and studded-partition walls to suit.

Shop Securely

Contact Us

Coventry Demolition Company
(a Division of Mossmead Ltd)
Ryton Fields Farm, Wolston Lane
Ryton on Dunsmore
Nr Coventry, CV8 3ES
0808 196 3734
Contact Form
Important notice!  COVID-19 update