Jump to content

Baxi boiler problem


wigeon jim
 Share

Recommended Posts

Hi, any heating engineers on here now what is wrong with my Baxi boiler, heating side is fine but the hot water is not nearly as hot as if used to be, it's only a few years old and was serviced last July but since then the hot water has been getting cooler, anyone know what's up,. Jim.

Link to comment
Share on other sites

I'm not a heating engineer but have had my fair share of Baxi boiler issues through the years.

First things first.... With the current cold ambient temperatures the hot water will likely not get as hot anyway... With a smaller output boiler (24-28kW) and a flow rate of 9-10 litres per minute the water temperature will rise by a given amount. If the starting temperature of the inlet water is colder then the outlet water will also be colder, unless you slow down the flow rate.

As LG says, it could be the diverter valve..... Turn off your heating and allow the system to fully cool. Feel the temperature of the heating flow and return pipes to make sure it has fully cooled. With the heating still turned off, turn on the hot tap and let it run, slowly close the hot tap until you get the water as hot as possible. Does it get hot enough? If so it could just be the inlet water temperature being lower than normal or it could be the heat exchanger blocked.  Leave it running for 15 minutes and then feel the flow and return central heating pipes. If they are hot then it's most likely the divert valve.

Most of the manuals for the Baxi boilers are available online and have a fault finding section in the back as well as part numbers should you need spares.

Disclaimer

I'm not a heating engineering so feel free to ignore all the above!!

Link to comment
Share on other sites

Apologies if this is a bit obvious, but after our boiler was serviced last year the hot water was a lot cooler than it had been before the service. On closer investigation the engineer had turned down the water temperature but we couldn't see it as it's an external boiler and those controls are inside the cabinet. A quick turn of the dial and we were back to normal.

Probably doesn't apply to you, but worth checking.

Link to comment
Share on other sites

I think Schmitty could be along the right lines. Presuming we are talking about a combi boiler, many of these boilers are fitted with a flow restrictor which can fail, particularly if you have quite high pressure cold mains. Reducing the incoming cold valve below the boiler {slightly} may improve temp at the taps.

It could of course be one of a few things, diverter valve passing, plate heat exchanger part blocked, thermistor etc which would need an engineer to test properly. If the boiler is only a few years old maybe it still has warranty? perhaps your installer could get a repair done under that.

Link to comment
Share on other sites

Thanks to the above,. The hot water in the kitchen near the boiler is not to bad ,you can just hold your hand under the hot flow but the hot in the bathroom above the kitchen is only half as hot even running a bath with only hot water its sill not hot enough,. Used to be OK as you needed to add cold water to the bath before,. Jim.

Link to comment
Share on other sites

Thats a bit low it should be about 12/13  on that with boiler.

do you have any type of water filter on the cold main before it goes into the boiler? is your water hard? i big give away is how much scale do you get in your kettle? the inside of your plate heat exchanger could be scaled up.

Edited by seph234
Link to comment
Share on other sites

The other test should be carried out as Schmitty said earlier, to check if the diverter valve is bypassing slightly.

let the boiler cool, turn on the hot water and see if the heating flow and return pipes get hot if they are then the diverter valve needs cleaning/replacing

 

Link to comment
Share on other sites

12 hours ago, seph234 said:

Thats a bit low it should be about 12/13  on that with boiler.

do you have any type of water filter on the cold main before it goes into the boiler? is your water hard? i big give away is how much scale do you get in your kettle? the inside of your plate heat exchanger could be scaled up.

Would that not affect both hot water AND the heating side though? If the heating is getting hot, surely the water should do the same? My boiler used more gas heating water! The burner is at max during the process! But once the heating is on a min or so the burner scales back. 

Link to comment
Share on other sites

It's probably a combination of lower incoming water temperature requiring more energy to heat it up and the PHEX scaling up, as someone has asked does it have a limescale inhibiter on the incoming cold supply and is the heating system clean and treated. Limescale and heat together quickly naffs things up. 

Link to comment
Share on other sites

5 hours ago, Lord Geordie said:

Would that not affect both hot water AND the heating side though? If the heating is getting hot, surely the water should do the same? My boiler used more gas heating water! The burner is at max during the process! But once the heating is on a min or so the burner scales back. 

No, different heat exchanger  for the heating and hot water.  the hot water uses a plate heat exchanger  which can get scaled up or sludged up if the heating circuit wasnt flushed properly. 

Link to comment
Share on other sites

had to replace the diverter valve for the same problem heating fine lacking in hot water   https://www.ebay.co.uk/itm/BAXI-COMBI-INSTANT-80E-80HE-105E-105HE-COMPLETE-WATER-VALVE-ASSEMBLY-248728/292602303239?ssPageName=STRK%3AMEBIDX%3AIT&var=591407355200&_trksid=p2057872.m2749.l2649 

easy to fit problem solved about 1/2 hr to fit 

sent them back the old unit as service exchange 

Edited by Saltings
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...