Adding a radiator & Flow and return

[HORNETUK]

Hello, first post looking fore some help please.
I am having a garage conversion and have had four quotes from very reputable companies. All have said adding one radiator to an exisiting system is never an issue, some have done over 400 jobs and never been a problem. When I have said thought you are meant to calculate boiler can cope they say you can, but one rad never a problem! Is this correct?

My other problem is my house is 9 years old and I have never had a boiler or heating issue in all those years, rads heat up immediately and are hot enough. On checking for flow and returns of the 9 rads I have 5 are thermostat side, 4 are other side. I know you can get thermostats that go either side so presume that not issue (they are Danfoss).

I presume these are all on right flow, return as am I right in thinking if one was on wrong way round e.g. return going into radiator it wouldn't get hot so quickly??

Just worried how builders will connect new rad when there is no pattern to my flow and return pipes?

Any advice / help THANKS

 

[dontknowitall]

If you get a plumber as opposed to a builder to fit the new radiator there should be no problem.

Ask your chosen builder if he recommends a plumber. Tradespeople don't work with unreliable/unknowledgeable people as it damages our own reputation!

 

[kirkgas]

technically you are correct a calculation "should" be done to confirm it is ok, however it is highly unlikely (therefore possible) that the boiler is working right at its max so wont take another rad, if you have a combi i can say it will def be fine, say a 28kw combi is fitted, the 28kw gives you a decent flow/temp to the hot taps, but it is unlikely your rads will total 28kw, if it is a system boiler, with a cylinder for hot water it could be 14-16kw, the easiest way is to do aa quick calc of your rads to get the total Kw of them all, (as a guide a 600mm high x 1000mm long double panel double convector gives out about 1.7kw) google stelrad radiators and look through the different size/style and find something similar to what you have, add all the kw then (add 3kw for water if you have a cylinder dont add anything if you have a combi), thats your total load, then you need to check what your boiler is a "vokera 28" is 28kw input NOT output so the actual load of a 28kw boiler is say 10-20% less depending on the age, if you google the actual boiler (or you have the manufacturers instructions look for the tech info and see what the "MAX OUTPUT" is,) this will tell you if the boiler will handle the extra rad, on the TRV's is just doesnt matter where the flow goes, rads usually get piped with the flow and TRV to the right "cause thats the way i was told to do it all those yrs ago) but depending on access or furniture etc it is perfectly acceptable to pipe the flow into the right or left, old TRV's needed to go on the flow now they can go on either, although i think there is still a slight preference foor the flow, so dont worry about it let the experts get on

 

[cdodds2004]

most thermostatic radiator valves are bi directional nowadays mate! look on the body of the stats sometimes have a arrow pointing both ways to indicate bi directional, if they are single direction then they have a arrow pointing one way and if that is the case and they are on the wrong pipe the thermostats will chatter when warm! no particualar side of a rad for flow and return they can go any way round aslong as the stat is on the correct end if single direction, but if bi directional then it makes no diffrence!

tell me how many radiators you have and roughly what size they are! and what boiler a kw output it has and ill tell you if a extra radiator will be ok!

If your boiler is a combi then i would say that you will be ok as the smallest combi is about 24kw which would do 20 average sized radiators! the reason it is 24kw is for the hot water output no heating, If its a conventional system then more care should be taken as these can be as low a 12kw but i would very much doubt any one would fit a boiler right on its limit,

 

[cdodds2004]

lol didnt see above post but atleast we both confirm the same thing we must be doing something right

 

[HORNETUK]

Kirkgas I did as you said and my boiler - Glowworm 40FF says MAX output 11.72KW, I have a tank system.
Doing the maths for all my rads, on the site you recommended, I came up with 8143 Watts. Does this mean plus the 3 for water takes me to 11.1? Meaning I'd just about get a rad on the current system? Or is this too close. Does it make a differance that the kitchen rad and another one never heat up, by choice, I presume the output of the boiler if they are all powered up at once, which they never are, also theHW is only on an hour in the morning and evening. What do you think? Thanks

Cdodds2004 I presume from the above info they have fitted one right on the limit?? Rads 11 sizes - 60x1110, 60x80, 40x1225 (Double), 40x50, 60x45 (Double), 40x1225 (Double), 40x50, 80x40, 60x55, 95x40, 50x50

Thanks again

 

[Bartdude]

I used a radiator chart I have and I made the heating requirement for your radiators to be 9.8kw,add 3 for hot water and already your boiler is underpowered before you add any new radiators. When you size a boiler you have to allow for all radiators to be working and if I was doing your work I'd recommend you change the boiler.

Your Glowworm is running flat out,do the rads get hot enough,quick enough? The past 2 winters have been a good test for all heating systems,how has yours coped?

 

[HORNETUK]

The 9 that are set to 3 or above come on within a couple of mins and all very hot. The two that are off, one of the large ones and the smallest come on immediately if I turn the valves up. Is it because water on early and late when heating off? But for 9 years always hot when needed never had a cold or slow radiator. So what you reckon, builders all say one rad no issue?
Thanks again

 

[Blackcatgas]

Just fit the radiator, It al be reeeet.

 

[maul]

the fact you never use 2 of your rads ever means you still have that unused capacity to utilise and doing so with your new rad wont be a problem in real terms. if at a later date you need to use all your rads then your boiler would be struggling to supply that amount of heat output but as your house is warm enough without using them then its highly likely your rads are a bit oversized anyway. if the house warms up quickly on cold nights and the boiler turns off on the roomstat its all good
if it was my house i would fit the new rad and only worry about the boiler being a little undersized when it is due for replacement.then you could go for a higher output model

a seriously undersized boiler will only mean it is unable to put as much heat into the house as the house loses when the weather is at its most extreme cold. this will mean it stays alight the whole time trying.
you could also uprate your house insulation in that situation to lower the energy requirement to heat it
but as you say your house is only 9 years old it should be fairly well insulated anyway. might be worth a look though

 

[moony]

it'll be alright - but not ideal.... one rad wont make much of a difference and i would go ahead and fit and advise that the boiler is at its capacity. if you were adding a 2 storey extension with 4 more rads then i would say go for a new boiler. but go ahead with the rad - then if at a later date you need to upgrade the boiler then put a bigger one in.

 

[HORNETUK]

Thanks for all the advice.

I take it a competent plumber will join up the pipes for flow and return OK! Also one builder looked at me like I was mad when I said I take it you'll drain system down to fit new one, surely that has to be done?

Thanks again

 

[ecowarm]

It is possble to add new rads without draining the system, freezing pipes or bungs in F&E

 

[dontknowitall]

This is why I said at the start, plumbers know how to plumb and builders know how to build.

 

[Rickster123]

Mr hooper is really pushing the stelrads this morning! Shame the posts are very old!

 

[PlumbBobBob]

Mr hooper is really pushing the stelrads this morning! Shame the posts are very old!

and he's now banned!

 

[stevetheplumber]

35 years ive added thousands of rads and they have always worked