Baxi Backboiler pump installation query.

[PeteW]

Hi. I have an elderly Baxi Bermuda backboiler, not sure of the exact model, but it is 30+ years old. The system has gravity fed hot water, vented system & pumped radiators with one 2 port valve & a thermostat in the hall. It is working ok with several issues.
Firstly our gas bills are enormous! Almost double the average for our type of property, although our usage is not excessive.
Secondly when the pump cuts in there is a banging from the upstairs radiator piping, loud & for several seconds, also adjustment of thermostatic valves on upstairs rads causes banging. Looking at the thermostatic valves they are the old unidirectional type, & the flow is in the wrong direction which would explain the banging. The only exception to this is the bathroom rad thermostatic valve where the flow direction is correct, but this seems to be plumbed to the gravity feed, which I understand is quite normal.
The pump was replaced about 4 years ago. Having trawed around as many references as I can from google (including this excellent forum) I wonder if the pump was replaced pumping in the wrong direction. Currently it pumps away from the boiler which is situated almost directly below. I have seen in one post that often with these older installations pumps often should pump on the return toward the boiler & installers can get this wrong.
My query is...If the pump is installed incorrectly, would the system continue to work ok as it has been for quite a while, with the exception of incorrect flow through the thermostatic valves & the high gas bills. If I reinstalled the pump so it pumped towards the boiler to test it, do I run the risk of any damage in this pretty basic system.
Just to say I'm not a plumber or heating engineer, but pretty handy DIYer!!
Thanks in anticipation.

 

[Simon F]

is the pump on the pipe to the top or bottom of the boiler?

 

[GQuigley67]

your large bills are down to your inefficient boiler, probably below 60% efficient, new boilers are 90% efficient so will bring your gas bills down

if the pump is on the return(they usually are) it should be pumping towards the boiler

 

[Gordon T]

A 30 year old boiler is never going to give you low bills. Unidirectional type TRV`s are the common new type. If pump was replaced wrongly 4 years ago why would the noise just start now? Try turning the pump around as you say. It wont make your bills lower but it might stop the banging. Failing that, as you said your no heating engineer, get someone in that is.

 

[diamondgas]

:welcome: to the forum pete 🙂

If the flow to all the TRV's are now reversed it does seem most likely that the pump has been installed the wrong way around.... The zone valve can also bang if the flow through it is reversed. Reverse flow through the boiler could also increase gas consumption as the thermostat phial is positioned incorrectly ...

Reversing the pump direction, if it is correct at the moment, will most likely increase boiler noise and flow temperature IMHO

 

[PeteW]

Wow! Thanks for the almost instant replies. Difficult to see if the pump is going to the top or bottom of the boiler, as squinting through the gap by the fire there is one pipe running to either side of the backboiler.

 

[PeteW]

Sorry should have said the banging has not just started, but been going on for ages. It was the latest gas bill that made me look more closely at the system!

 

[jtsplumbing]

No matter what you do to a system this old it will be cost`y to run . if you have limited space get a quote to fit new Baxi HE back boiler and cut your running costs by at least 35% when was boiler last serviced ? it may be burning to much gas, Remember when these were put in gas was cheep.

 

[PeteW]

Regularly serviced, last one about 9mths ago. I do understand these are not economical systems, but as we probably won't be here longer than a couple of years, will keep the old faithful going if possible. Just want to be sure it's set up correctly. Any other way I could confirm the correct pump orientation?

 

[diamondgas]

Regularly serviced, last one about 9mths ago. I do understand these are not economical systems, but as we probably won't be here longer than a couple of years, will keep the old faithful going if possible. Just want to be sure it's set up correctly. Any other way I could confirm the correct pump orientation?

A GSR engineer could follow the pipes through the chimney breast and correctly identify F&R ... That's about the only way I can think of 🙂

 

[stani]

are you sure its a zone valve, is there any wire going to it?

 

[PeteW]

Hi Stani, yes its a honeywell 2 port with associated wiring. Further investigation with head wedged down under the airing cupboard, a torch & mirror show that the direction arrow for flow on the valve & the pumped flow are both going in the same direction, ie. both headed out away from the airing cupboard under the floorboards, which doesn't seem right to me........

 

[diamondgas]

Hi Stani, yes its a honeywell 2 port with associated wiring. Further investigation with head wedged down under the airing cupboard, a torch & mirror show that the direction arrow for flow on the valve & the pumped flow are both going in the same direction, ie. both headed out away from the airing cupboard under the floorboards, which doesn't seem right to me........

Well pete that kind of says to me that the pump is on the right way around and the TRV's are incorrectly installed ... May have been that the boiler and controls are newer than the radiators and were added incorrectly?

 

[stani]

Well pete that kind of says to me that the pump is on the right way around and the TRV's are incorrectly installed ... May have been that the boiler and controls are newer than the radiators and were added incorrectly?

got to agree, the controls seem to be newer, I only asked re the valve just in case it was a Dumball valve which was used on these systems quite a lot,

 

[PeteW]

Have a feeling I didn't explain my last post very well. The valve & the pump are on seperate pipe lines, so there are two pipes heading away from under the airing cupboard one with the pump on, one with the valve on, both direction arrows are showing the flow away from the tank/airing cupboard. I assume one pipe is flow & one return, so they should not be the same direction?
While I'm at it, can I just say this is my first post on this forum & i'm knocked out you folks took the trouble to reply so quickly, so thanks a lot.

 

[diamondgas]

Have a feeling I didn't explain my last post very well. The valve & the pump are on seperate pipe lines, so there are two pipes heading away from under the airing cupboard one with the pump on, one with the valve on, both direction arrows are showing the flow away from the tank/airing cupboard. I assume one pipe is flow & one return, so they should not be the same direction?
While I'm at it, can I just say this is my first post on this forum & i'm knocked out you folks took the trouble to reply so quickly, so thanks a lot.

Okay that makes a difference Pete ... reverse your pump mate!!!

You ever heard of a busmans holiday? Well plumbing/gas engineering isn't something you can switch off Pete, well for most anyways Personally i enjoy helping others🙂

 

[PeteW]

Ha! Ok well I know what i'll be doing tomorrow! Friday is pump reversal day! Know what you mean about a busmans holiday....my line is computers & all that stuff....I seem to be tec support for family, friends & half my local area! But as you say, it's good to help others.
Thanks again.

 

[Simon F]

if the pump is fitted with some means of isolation it should be a relatively simple job, assuming the valves close of there is no need to drain the system.
worth going shopping before you start for 2 new pump washers in case they break up when you open the fittings.

 

[GQuigley67]

if you have to drain the system then remember to put some inhibitor in, and if the pump has 2 isolation valves and are the type u need to use a screwdriver to close then they may also leak, best to replace if they do

 

[PeteW]

Just a quick heads up on my pump saga. Isolating valves screwdriver type, rubber washers in good nick! Ten minute job, but what a difference! No banging when the pump cuts in, all thermostatic valves working like they should with no banging when trying to set, boiler quieter......in fact a result!
Wouldn't have had the confidence to switch pump flow direction without reading earlier posts on the forum & posting my first query here, ain't it happy when things go right. Thanks for your very speedy & useful input. Pete

 

[diamondgas]

Thanks for letting us know Pete 🙂

 

[stevetheplumber]

you do realise we will all be chasing you for it support for the next 20 years lol

 

[GQuigley67]

good you got it sorted and lucky your isolation valves didnt leak !! lol 😛

 

[jtsplumbing]

Now what about paying the bill, invoice is in the post.
:icon12:

 

[Simon F]

Happy to take Pay pal. :lol:
Good to hear its gone well.