New Radiator problems

[1bit]

Hello

I have installed a new Radiator in the living room replacing one that was there, the differences are that it takes longer too heat up than previous one and others downstairs, and when it does its slightly cooler on the bottom, ie. the top is red-hot and bottom is hot.

it is a 'triple' radiator that replaced a double and I was thinking that maybe why it takes a bit longer for the front panel to heat up as the back feels hotter, I am assuming it has to go through the back, middle then front panels...so that may be why its a bit slower?

- also we have replaced the valves on it, she just went and bought them and I fitted them - all other valves in the house are lockshield and thermostat valves and most of the thermostat valves have been installed on the wrong ends of the radiators (by previous owners) which was causing banging when on lower settings forcing us to leave them all on full open (until we replace those too)... when she gave me the valves I noticed that the opening through which the water goes through was small?? like about 1/3rd of the entire 15mm radius?? I wondered if this would cause problems with balancing etc and now wonder if this plays a part in my problem?

can I ask? - if your changing all the rads & valves in your house to new ones...should the valves all be the same? as Iam wondering if you get some that have better flow/openings that others (like in my explanation above about these new valves ive put on) you could end up with these sorts of issues? - I put a towel rail in kitchen and tall vertical rad in small bedroom upstairs and both of these had big chunky 'tap' like valves that had big openings allowing for good flow, these heat up perfectly, but the new rad downstairs is slow at heating and is hotter on the top and the valves on this one were poor for allowing flow...well I thought they might be.

can anyone offer some help and advice on this please?

thanks

 

[AWheating]

is the room cold? if not then why do you want the rad to be hotter?

welcome to the forum.

 

[Subby]

Do you have a room stat?

 

[lame plumber]

u need to rebalance your system

 

[henly1234]

in older systems towel radiators in bathrooms are generally fed from the primary pipes in other words they are not controlled by the normal means and come on even when the CH is not turned on.

TRVs work on air tempeture and not water tempeture as do room stats, trv outlet and inlet are designed to flow at optimum flow rate and they are all similar, if your rad is hot at the top and cold the bottom it is generally a sign of sludging, however that depends on the time it takes and the position of the rad on the system rads will always be a little bit hotter at the top because hot water rises and cool water sinks thats why your valves are situated where they are ie at the bottom of the rad hot comes in rises to the top loses it heat and sinks and at the other end.

Rads will always be hotter than the room temp, wait for the system for about an hour before you test, then there should be about a 1 dgree diff between flow and return.

 

[doitmyself]

most of the thermostat valves have been installed on the wrong ends of the radiators (by previous owners) which was causing banging when on lower settings forcing us to leave them all on full open (until we replace those too)

Most modern TRVs are bi-directional, so it doesn't matter which end they go. But if the TRV has a single arrow on the metal body, this must point in the direction of flow (toward rad on flow, hotter, pipe; away from rad on return, cooler, pipe). Banging can also be caused by the pump on too high a setting.

when she gave me the valves I noticed that the opening through which the water goes through was small?? like about 1/3rd of the entire 15mm radius?? I wondered if this would cause problems with balancing etc and now wonder if this plays a part in my problem?

That's perfectly normal and won't be the cause of your problem. Don't forget that 15mm pipe can carry about 6kw of heat but the TRV will be only carrying a max of about 2kW.

should the valves all be the same? as Iam wondering if you get some that have better flow/openings that others

Mixing valves is perfectly OK. It's not a matter of better flow, larger opening but having the correct flow, which is controlled by adjusting the lockshield valve when the system is balanced.

Your system needs balancing.

 

[1bit]

Thanks for all the replies, most informative and welcoming

ok, attempt no.2 as my first reply was lost due to a time-out, seems you only get 'x' minutes to type your reply then your logged out

....................................

Yeah it seems the heat top/bottom issue is just normal, the room heats up fine but seems to take longer than previously, the VTU output is correct for the room size, the old rad was under the window and I have moved it 4 ft to the right, it may be due to the new location, the living room is open plan to the dining room via an arch and currently there is no door on the kitchen entry yet, could be draft pulling the heat through to there before it drifts across too sofa, I will cover the door opening and see if it helps.

also, I just turned off all the rads upstairs and the one in the hallway downstairs, this hallway one is fed first before the newley installled rad -since doing this we can hear the water pumping through quite strongly on the rad and it seems to be emitting lots more heat - so it would seem that it simply needs balancing as already noted by other members, I have a Multi-Meter with a Temp gauge on it, I think I will do this AFTER I install the Diner's new Rad.

would just like to say thank you again for the advice offered, Iam pleased to know that mixing valves is fine and being slightly lower in temp on bottom is normal... thanks again

EDIT: btw - the TRV's installed on current rads (by last owners) are one way and have been installed on wrong side, this causes banging when using setting between 1 and 2 , so we either have them on FULL OPEN (5) or OFF (*) - we arent bothered about TRV's so removing them as we go and putting standard valves on

EDIT 2: these were the valves we used: Torino Angled Rad Valve on screwfix...no link in case its not allowed, product: 43354

thanks again

 

[mwebb]

hi. your system just needs balancing. the valve at the opposite end to your trv will need cutting back on the radiators which are nearest to the start of your radiator circuit and the ones at the end of the rad circuit will want to open more fully. this will sort problem out. and you can mix any manufacturer of valve.

 

[SimonG]

ok, attempt no.2 as my first reply was lost due to a time-out, seems you only get 'x' minutes to type your reply then your logged out

When you log in tick the little box, it won't kick you out.