Radiators -

ally18

Hi,

To be brief:
Have had the same c/h system in my house for over 19 years, its an old maxi boiler that provides the hot water and heating. There are 7 radiators attached to it. Boiler had been serviced in the past when married but not every year. It tended to be only when its been thought about. I am now single and a little worried about how much longer it will last so am making sure its serviced regularly.

My concern is the valves on the radiators. Each valve at either end of the radiators has nothing over it, it is purely a little spindle which you have to use pliers on to get it to move. Since living on my own, when I had the money, I have had the whole system flushed to make sure it is thoroughly cleaned, had the bathroom rad changed to a towel rail but I wondered if I needed to get new valves fitted on the radiators to make them more 'operable'. I had a quote back in April for £180, is this reasonable and would it be a good idea. I dont have a lot of cash though. I noticed yesterday that the rads all seem to be hot at the top but luke warm at the bottom. Because of them not having proper valves on, Im reluctant to try and sort anything out myself incase I flood the house!

I ended up having two different plumbers to do the jobs because they dont seem to want to come back. One bloke I asked to come and sort a problem ended up charging me £30 because the radiator wasnt actually switched on, but I dont know if they are on or off.
Any advice would be welcome please.

A.Penny.Saved

You might be able to get some replacement radiator valve caps IF the valves are otherwise okay and not leaking, otherwise it would probably be best to have them changed. Thermostatic radiator valves are usually used now, especially on Combi boilers but I guess yours is not one those. The caps just push on and pull off so fitting shouldn't be a problem providing they match the valves. So it might be worth getting only one set to make sure they fit okay before purchasing as many as needed. There can be different size valve heads, the bit that sticks up on the Radiator valve. The cap pushes onto that and allows it to be turned. There is a lockshield valve on one side and a wheelhead valve on the other. It's only the wheelhead valve which is turned on and off, the lockshield valve shouldn't be altered because it can unbalance the system leading to certain radiators heating up more than others. The question is, which is which on each radiator? The hotter pipe on one side would be the flow where the wheelhead is fitted and the slightly colder pipe would be the return where the lockshield valve is fitter but the difference wouldn't be that great so telling in this fashion would be difficult without a temperature sensor. Tracing the pipes back to the boiler is another way but they might be below floorboards. Maybe there is another way which someone can suggest.
Amazon sells a set of caps that can be fitted to different size valve heads but others online look better IMO but you would need to get the correct size. The Amazon ones are quite expensive at £6.42, whereas the others can be purchased for under £3 a pair. Try measuring the size of the valve head/spindle, I have a valve in front of me because I was checking for something else a couple of days back and that measures about 8mm x 5mm and the one on my Rad which is quite new measures about the same. One site online say the ones they sell are 7mm x 3mm which might not fit newer valves. If yours are 19 years old, they might be a different size.



Alternatively you could purchase a pair of full radiator valves which cost only £1.78 and see if the caps from those fit yours. Toolstation sell them for that much and is a company I recommend because they have always been very helpful when I have phoned them asking for information on their products, going and finding the information I have asked for and calling me back. The 15mm variety are the normal ones and refer to the copper pipe size, 15mm being commonly used but 10mm or even 8mm is sometimes, check the width of the copper pipe to determine that and get the correct size to help ensure they are more likely to fit.

Toolstation Radiator Valves as a cheap way to get sets of replacement Caps

Toolstation have branches throughout the UK and you could visit if there is one local to you. If you check the approximate size of your valve bodies where there is a lip which the caps clip onto and see if the ones you receive look of a similar size before removing from the wrapper, if they don't look like they may fit the width of the valve body then you can return them for a refund. Toolstation offer free delivery for orders over £10 so you might find something else to order with them such as bulbs or similar so you can get one pair delivered free. Ordering the rest that you need will add up to around £10. You can even phone and ask for a catalogue which they will send you, I regularly get sent a catalogue.

If you were going to have valves replaced, it might be worth replacing them with TRV's Thermostatic Radiator Valves so they switch off Radiators depending upon the room temperature. The prices of those can vary quite a lot, Toolstation do some which are pretty decent for £8.98 but it's only one valve for that, that doesn't include the lockshield valve, so you would need to get one of those as well. If you wish to do that it might be worth asking how much it would cost to fit those. On an old boiler you probably couldn't have every radiator fitted with TRV's, a couple of Rads would need lockshield valves so water can flow in the system. Otherwise a bypass valve has to be fitted, Combi boilers sometimes have auto bypass systems to compensate for having TRV's fitted to every Rad, my boiler does. I'm about to replace a few Radiators myself. Replacing the valves with the Toolstation TRV's and separate lockshield valves and add isolating valves so the Radiators can be removed when I re-decorate. I have a lot of redecorating to do.

I quite like the look of these.

Ambient Dual Flow Thermostatic Rad Valve £8.98 but currently out of stock, I hope they get them back in stock soon as I already have one of them here and want some more to match it.

Search google for "replacement radiator caps"

As to your radiators and the temperature I must add that I'm not a heating engineer only a keen DIYer, so I'm only going to guess what might be causing the warm patches in your radiators. You say that your heating system has already been flushed? Was there any colder patches near the bottom before they flushed the system? Was it only some radiators? Radiators rust from the inside and the rust enters the water along with bacteria and that forms a sludge in the bottom of radiators which could if severe enough affect the temperature. Central heating protector should be added to a heating system to help prevent rusting and bacteria gowth and needs to be replaced every few years, I think that inhibitor manufacturers say every year. Central heating flushes are meant to flush the sludge out but I wonder whether all they did was move it into other radiators. Maybe they didn't actually do anything at all apart from look busy to earn their money? I have seen on other forums, some heating engineers saying they like doing central heating flushes because it's a good earner once the gear has been purchased and not always necessary. Less scrupulous people might say they are going to do it and do nothing or do it partly but not completely.

I have removed CH radiators myself on a few occasions so I have seen some of the muck that can come out of them, on an older system it could be a lot worse.

There are some experienced heating engineers on this forum so they might be able to give you a better opinion on what might be causing it. Hopefully after I bump your topic someone else can comment on that.

A.Penny.Saved

andrew-b wrote: »

£180 is a good price for that...assuming that's supply and fit of TRVs (the type of boiler is irrelevant to whether you fit TRVs.. just don't put a TRV on the rad in the room where the thermostat is located).

The cheap alternative (using pliers will end up rounding off the corners on the spindles) is to get a replacement cap. If you don't screw in place you only need one as you can use it on all valves if they are the same ...i have a spare cap that i kept when i replaced bathroom rad with a towel rail and i use it as a simple way to turn the lockshield valves off when i want to isolate/remove a rad. I suppose if you have trouble sourcing one you could make your own "key" from a piece of wood with a suitable size hole cut out!

Don't worry yourself about what is flow or return (though it's pretty easy to tell with the different of temperature with the back of your hand) most TRVs are bi-directional and it doesn't much matter whether the lockshield valve is on flow or return as the same result is achieved whichever one you turn if you always change the same one!

It was me who mentioned TRV's, she didn't. She indicated that her current valves were regular wheelhead/lockshield types but without the caps, so the flow and return would be relevant if she was replacing the caps. A few replacement valves for the Caps would cost a lot less than £180. That quote doesn't mention what types of valves would be fitted so the difference could be quite a lot if the quote was only for wheelhead/lockshield replacements, which wouldn't really be needed if the current ones are functional and not leaking. Old valves can leak, I have a few that are leaking and in a bit of a mess which I am about to replace. But if hers are okay then it would probably be not worth replacing them ATM unless she wanted TRV's to auto adjust the room temperature.

As for hot at top and colder at bottom ...that is a sign of sludge gathering at the bottom of the rads. You mention having the system flushed but do you know if that was a powerflush (they would have hooked up a piece of machinery if it was) which is pretty thorough (if used correctly) or just a system clean where the system is drained a chemical is added and left to circulate ( a month is preferable but heating guys might only do it for an hour...!) and then drained down and refilled.

Also do you know if they added central heating inhibitor after? The two big brands of inhibitor are Fernox or Sentinel...if they don't stick on a label somewhere, heating guys often leave the empty container next to the header tank in the loft so it's easy to tell what has been put in there! No need to readd it every year...unless your replacing/removing rads.

To swap the valves would mean draining the entire system down (usually - but there are ways to avoid it by shoving root vegetables in the right place!!) ...you would also need an olive puller to pull the old olive off the pipe so you can remove the nut holding the valve on..though you might be able to reuse the nut and so avoid it.

We had a couple of valves changed when we had a boiler change...far easier then as the whole system is drained down so you could save a bit of money in the long run if you waited until a boiler change before swapping the valves. I'd swap the valves myself but if your not confident in your abilities and worried of flooding the place best off paying someone to do it!

Realistically you may need to start putting money aside for a new boiler if you can as 19years is a pretty good innings (doubt you'll get that from modern but more efficient boilers!). Still it's being serviced now and again hopefully it will get you through another winter.

P.s. are you sure you didn't mean Baxi! Maxi's were a car my Dad used to have!

Baxi's are a make of boiler and were what came to mind when I saw her mention maxi, but there was a boiler model with maxi in the name called Maxi Comfort, it's not reserved for rusty old cars. They are made by Radiant.

19 years is quite a long time for a boiler, it must be nearing the end of it's life and will probably need replacing in the near future.

gas4you

Sorry, but so much text in above posts just makes me switch off