topic Re: BAXI Gas Central Heating Boiler query in Tech Help - Software/Hardware etc

BAXI Gas Central Heating Boiler query

shutter — Fri, 17 Jan 2020 08:26:42 GMT

We had a new GCH boiler installed last November...

and I think I need to bleed the rads cos some of them are not as hot as others.

On our "old" boiler, there was a flexi link pipe from the mains water input with a large black switch that I could open and inrease the water pressure as shown on the dial, to ensure that it remained in the green sector.

whilst this boiler has the isntruction

When I look underneath the boiler,...

. I do not see a GREEN lever.... only one yellow, and three black....

Would I be correct in assuming the black one on the right is the one that the lable is referring to?

Whilst typing and posting this thread, I notice some markings on the plate above....

so I have cropped the pic to show better

Re: BAXI Gas Central Heating Boiler query

MisterW — Fri, 17 Jan 2020 08:59:51 GMT

The markings would seem to indicate from the right

black - feed to radiators

Black - hot water feed

Yellow - unmarked

Pipe without tap - return from hot water

Black - not very clear from photo , possibly return from radiators

By elimination would that say the yellow one is the one to allow repressurise.

TBH best option has got to be to speak to the installer hasn't it?

Re: BAXI Gas Central Heating Boiler query

shutter — Fri, 17 Jan 2020 09:05:42 GMT

@MisterW Hmm... not sure about your elimination there.... I was assuming that the words " Green" and "under the right side of the boiler" would be the one most to the right ( regardless of the colour black )..

and that the YELLOW one was for the GAS supply cut off

But as the one "under the right side" is clearly black and there is another black one there, the confusion of which of those two "should" have had a green tap fitted. is the reason for the query.

I posted on here, cos it seemed that, perhaps, I am not the only one that has this boiler fitted and someone would know... It`s not desperate a the moment... so will leave it posted, as is... and then see about contacting BAXI for clarifications if needed.

thanks for the input..

Re: BAXI Gas Central Heating Boiler query

MisterW — Fri, 17 Jan 2020 09:35:26 GMT

I hadn't considered that yellow could be gas , but you may be right.

I think baxi or the installer is the best option

Re: BAXI Gas Central Heating Boiler query

shutter — Fri, 17 Jan 2020 09:46:23 GMT

@MisterW After giving your reply some thought... and doing elimination... and trying to guess the meanings of those symbols... I reckon it is Definitely the most right hand one.... as that will provide water TO the rads...( as you said ) .. and this is where the water pressure is impotant..... .and the one with the tap, will provide water TO the boiler for the hot water taps on the "outlet" side.

Just found that there is an "online" email thing to BAXI... so will write it up on there and send it , just to be sure.

Thanks for your input

Re: BAXI Gas Central Heating Boiler query

Baldrick1 — Fri, 17 Jan 2020 09:53:38 GMT

@shutter

I would question whether it’s any of these controls. If you look at it logically, what this green tap does is bleed the incoming high pressure rising main into the central heating circuit to maintain an acceptable pressure in the central heating loop when radiators are bled.

Can you follow your pipework and identity this rising main? This should be connected to the green valve.

Also reading between the lines I suspect that this green valve is momentary action, that is, it has a spring return to off to stop it being accidentally left on and overpressurising the radiators.

Is it possible that you are looking in the wrong place or the installer never fitted it?

Re: BAXI Gas Central Heating Boiler query

maranello — Fri, 17 Jan 2020 10:30:25 GMT

@shutter

Have you tried reading the user manual?

Page 17 looks relevant

Just a suggestion

Re: BAXI Gas Central Heating Boiler query

jgb — Fri, 17 Jan 2020 10:39:28 GMT

@shutter

I do not think any of the taps (black or yellow ) are used to repressurise the system.

The yellow tap is the gas feed to the boiler judging by the gas bleed nipple on the end.

Assuming it is a Combi boiler, the three black taps are the feed from the boiler to the radiators and the return from the radiators to the boiler, and the hot water feed (looking at the symbols stamped into the boiler casing that is the middle black tap).

Having done a bit of googling, the only reference I can find on a Baxi boiler to a green tap for repressurisation is for an Easy Fill Permanent Filling Link which does have a green sprung tap, but appears to be an optional fitment. See here:

https://www.bhl.co.uk/baxi-easy-fill-permanent-filling-link.html

and

It does not appear that is fitted to your boiler.

Therefore, before touching anything under the boiler, I think you need to go back to the installer to ask what provision he actually made for repressurisation.

Re: BAXI Gas Central Heating Boiler query

jtr — Fri, 17 Jan 2020 11:18:27 GMT

I would first check the radiator valves then bleed the radiators to see if there is air in the system ? Then pressure the system if necessary putting it back into the green zone.

Re: BAXI Gas Central Heating Boiler query

shutter — Fri, 17 Jan 2020 13:58:21 GMT

@Baldrick1 Thanks for your input.... because of that, I pulled out the tumble drier, to check the pipe runs... and... lo and behold,.... the old flexi pipe and tap are still in place !

so... I gave it a quick tweek, and it has repressurised the radiator pressure... !

Wonder why the installer left that sticker about the green tap, on the front of the boiler...he never said ..."oh by the way... if you need to repressurise the system, use the one under neath the worktop surface, as before........"

ah well.!

So... para 1... agree !

para 2.... Yup ! as mentioned above.

para3 ... again... Yup !... as mentioned above ! ! .

Thanks

@maranello Yes,... the manual shows the same information as the sticker on the front of the boiler !

@jgb Thanks for your input too,.... all good info...and thanks for taking the time to "google" for more info.... and .... as you say... "it does not look as though the installer fitted the green tap "...

however.. problem solved as mentioned in reply to Baldrick.

Thanks.

p.s. I gave the "fix" to Baldrick, but you can take half away from him, for your diligence ... thanks again....

@jtr that is exactly what I was doing, before I posted the query... the query was about the green tap... to repressurise the system... see reply toBaldrick above.

Re: BAXI Gas Central Heating Boiler query

VileReynard — Fri, 17 Jan 2020 22:43:01 GMT

Why is the hot water and the radiator temperature turned up nearly to max on the front of the boiler?

Bit unusual.

Re: BAXI Gas Central Heating Boiler query

shutter — Sat, 18 Jan 2020 08:49:03 GMT

@VileReynard dunno ! ... that`s the way he left it... seems ok to me... ! what is "usual" if i is "unusual" ? ? ?

Re: BAXI Gas Central Heating Boiler query

Mook — Sat, 18 Jan 2020 09:25:45 GMT

For my boiler @shutter usual would be to have both the dials set between 5 and 6 if you base the dials on a clock.

Re: BAXI Gas Central Heating Boiler query

VileReynard — Sat, 18 Jan 2020 13:55:54 GMT

Assuming your boiler is an appropriate capacity, maxing out the two controls means your hot water ought to be scalding hot and you will have super hot radiators (after you have bled each one).

This causes high gas bills.

Re: BAXI Gas Central Heating Boiler query

jgb — Sat, 18 Jan 2020 14:13:09 GMT

The appropriate and most efficient settings for any installation depend on several factors including how you use the heating (is it on all/most of the time or only for a few hours morning and evening - in which case you want rapid warm up, hence a high setting); what other controls are installed - e.,g. thermostatic radiator valves etc; what is connected to the hot water system - e.g. some thermostatic showers specify a minimum hot water temperature to ensure effective and efficient mixing - usually around 60 to 65 degrees C at the shower (so, unless your boiler is "miles" away from the shower, an output hot water temperature of 70 to 75 degres would probably be adequate) - but if is there is no such requirement a lower and safer temperature would be appropriate.

You can only determine the most efficient and comfortable settings by trial and errror.

Re: BAXI Gas Central Heating Boiler query

shutter — Sat, 18 Jan 2020 15:36:39 GMT

@VileReynard

@VileReynard wrote:

Assuming your boiler is an appropriate capacity, maxing out the two controls means your hot water ought to be scalding hot and you will have super hot radiators (after you have bled each one).

This causes high gas bills.

Interesting concept..... "causes high gas bills"....

Surely,... if you want your "heating" to work, you must make the radiators hot enough to warm up the surrounding air, and "convect" that warmed air, around the space you are trying to heat...

once the air temperature has been raised to the required "ambient temperature" ( set on the controls) the gas is then shut down, and the radiators continue to convect the warmed air around them...

if you have the "hot water in the system" just warm, then that will use more gas to heat the air around the raiators and for a longer time, to reach the "ambient" temperature you have set...

conversely... if the hot water in the system is near boiling, then the air will be heated quicker, and after the ambient temperature is reached, and the gas is shut down, it will take longer for the radiators to cool down, thus providing more "latent" heating time than a "warm" system that you are suggesting .

By the way.... you sidestepped answering my question in post number 12

@VileReynard dunno ! ... that`s the way he left it... seems ok to me... !

what is "usual" if i is "unusual" ?

Re: BAXI Gas Central Heating Boiler query

VileReynard — Sat, 18 Jan 2020 16:35:50 GMT

I didn't sidestep anything - @Mook answered your query about what is "normal".

It seems obvious that if you run that boiler at a higher than necessary temperature it is going to be a less efficient system.

I suggest you check with the engineer when your boiler gets its annual service.

Re: BAXI Gas Central Heating Boiler query

Baldrick1 — Sun, 19 Jan 2020 11:41:39 GMT

@shutter

If you want to get the maximum efficiency out of your condensing boiler then you need to set the temperature so that the return flow is less than the dew point, that is, about 55 degrees C. The feed temperature has to be higher than this for the condensing cycle to work but unless the return is sufficiently low the condensing cycle fails and the boiler efficiency drops.

Re: BAXI Gas Central Heating Boiler query

shutter — Sun, 19 Jan 2020 14:26:59 GMT

@Baldrick1 Thanks for the input. which is totally confusing me. ! ! ...

As I understand it.... the "dewpoint" can change hourly,...( as confirmed by listening to VOLMET channel )

Re: BAXI Gas Central Heating Boiler query

Strat — Sun, 19 Jan 2020 14:38:42 GMT

I have come across lots of people who, in Winter, turn the room stat up full when returning home.

They do this in the belief that the house will warm up quicker.

I used to have a book of formulae pertaining to installing and setting up central heating.

Things like flow rates and outflow temperature v return temperature and balancing radiators.

Thankfully I don't have it any more.