Very slow flow of hot water from vaillant boiler

[funtins]

Hi,

basically, the flow of water seems very weak but when I check the pressure on the boiler, it says its about 1.5 bar. I thought this would be enough so dont get what the issue is.

Also, in the hope that this would solve the issue, I would turn the boiler off and fill the water up as much as it would let me and then turn the boiler back on. This didnt fix the issue either.

Does anyone have idea how I can fix this? It used to work fine and has been playing up during the last week or so.

Any help is much appreciated.

 

[terryplumb]

The pressure gauge on the boiler reflects the pressure in the central heating circuit ,routed thru the boiler.it has nothing to do with the hot water pressure from your taps. Is it your taps that you refer to ??

 

[funtins]

The pressure gauge on the boiler reflects the pressure in the central heating circuit ,routed thru the boiler.it has nothing to do with the hot water pressure from your taps. Is it your taps that you refer to ??

oh right! i had no idea. yes taps and shower especially.

 

[terryplumb]

What is the model / name of your boiler ,besides vaillant. Do you have a hot water cylinder or is it a combi boiler ?

 

[funtins]

What is the model / name of your boiler ,besides vaillant. Do you have a hot water cylinder or is it a combi boiler ?

its an ecotec plus 837 mate. its a combi.

 

[terryplumb]

I assume your cold water on kitchen tap is very good pressure ,and ALL your hot taps / shower are suffering from poor flow . if that's correct check the cold water feed into the boiler does not have any isolation valves that are partially closed. Having established the cold feed to the boiler is not restricted ,then the problem is within the boiler.

 

[funtins]

I assume your cold water on kitchen tap is very good pressure ,and ALL your hot taps / shower are suffering from poor flow . if that's correct check the cold water feed into the boiler does not have any isolation valves that are partially closed. Having established the cold feed to the boiler is not restricted ,then the problem is within the boiler.

hi. just had a quick check of the pressure of hot vs cold and its really not too different. hot is definitely less though. the biggest issue seems to come when the shower is used.

and sorry i dont know what you mean by the isolation valves being partially closed and cant work it out from a google search so i've attached pictures hoping that you can point out what i need to check?

thanks again

 

[terryplumb]

They are all OK .if there is not MUCH difference between hot and cold at the kitchen sink ,in terms of flow of water, make sure your mains stop cock is fully open. Its quite usual with a combi that the hot tap doesn't quite give as high a flow rate as the cold. Both are under mains pressure but the cold is pretty much unrestricted ( little resistance in pipework ), the hot however is restricted thru the boiler. Are you sure its not just a problem with the shower ? What kind of shower do you have ? Manual mixer ,thermostatic mixer ? Sometimes the shower head gets scaled up and reduces the flow ,or filters get blocked up in the Inlets.to rule out the boiler ,you can do a flow test on hot kitchen tap. Put a bucket or summat under the tap ,turn on full and time 1 minute .turn tap off and then measure how many litres of water are in the bucket. 8 or 9 litres in 1 minute would be expected ,minimally. Anyway ,its past my bed time !!! Let's know how you get on.

 

[funtins]

They are all OK .if there is not MUCH difference between hot and cold at the kitchen sink ,in terms of flow of water, make sure your mains stop cock is fully open. Its quite usual with a combi that the hot tap doesn't quite give as high a flow rate as the cold. Both are under mains pressure but the cold is pretty much unrestricted ( little resistance in pipework ), the hot however is restricted thru the boiler. Are you sure its not just a problem with the shower ? What kind of shower do you have ? Manual mixer ,thermostatic mixer ? Sometimes the shower head gets scaled up and reduces the flow ,or filters get blocked up in the Inlets.to rule out the boiler ,you can do a flow test on hot kitchen tap. Put a bucket or summat under the tap ,turn on full and time 1 minute .turn tap off and then measure how many litres of water are in the bucket. 8 or 9 litres in 1 minute would be expected ,minimally. Anyway ,its past my bed time !!! Let's know how you get on.

here is the shower mate...previous owner of home told me its "electric" but the hot water comes from the boiler itself.

i guess the next easiest thing is to de-scale the showerhead?

 

[terryplumb]

Just remove the shower head off the hose , and see if there is any difference to the flow.
********
Edit ,aqualisa do a whole range of showers and I am not sure what model yours is ,but it looks as though it MAY have a pump in it ?? Does it have an electric supply ? Any led light near the on /off button ? Do you have a model number / name to identify it ?

 

[ReganAndCarter]

Looks like one of these -

https://www.screwfix.com/p/aqualisa...gclsrc=aw.ds&dclid=CIyzr_np9dgCFdYw0wod0joBtw

 

[terryplumb]

Looks like one of these -

https://www.screwfix.com/p/aqualisa...gclsrc=aw.ds&dclid=CIyzr_np9dgCFdYw0wod0joBtw

Sure looks like one . what's the benefit if fitting this to a combi ? 300 quid for a not particularly swish looking thermostatic mixer ,am I missing something ???

 

[funtins]

yes it does look like the one quoted.

 

[funtins]

lads, its fixed. you may not believe how, here's the story....

i did as advised above and took the shower head off and checked of the flow was different. it wasnt. so i knew it wasnt the head. the bathroom tap was getting hot water just fine, as was the rest of the house. so, i thought it must be the electrics within the shower not knowing how much water to grab, or being confused about the hot water in some respect. so i just thought why not turn it off and on, hoping it would reset it to default settings. i couldnt find a switch for it so i went to the fuse box and turned the upstairs electrics off (where the shower is) and turn it back on again.

...its all working now! seems to be working very well too! i think the electrics in the shower got confused by something. Not sure what. maybe it was because i recently had issues with the boiler and messed around with it a bit.

 

[chrisw99]

I'm surprised you have an electric shower with no isolation points for the electric other than the fusebox?