heatslave 12/18 no instant hot water

[bluesriff7]

greenstar heatslave 12/18 oil combi boiler, 9 years old.
when my boiler fires up first thing in the morning its been making a banging nose but it heats up the hot water ok
and central heating works ok.
the hot water is set to come on by the timer on the boiler on at 5.15am off 9.am. if i use a lot of hot water after 9.am
i don't get any instant hot water. boiler does not fire up when turning hot tap on.
is it worth getting the boiler fixed.

 

[SimonG]

Yes it's worth getting the boiler fixed.

 

[bluesriff7]

Yes it's worth getting the boiler fixed.

I had a new flow switch fitted last year and it was full of scale, thats when the engineer found out about the instant hot water issue. He never got back to me. He did say get in intouch with bosch?

 

[SimonG]

Worcester wont be interested on a 9 year old boiler. Are you in a hard water area? Is it the first time the flow switch has been changed?

There are a couple of other things that can cause this that any oil engineer should be able to sort quite easily.

 

[SJB060685]

Is this a recent problem?

 

[bluesriff7]

Is this a recent problem?

Hard water yes. Flow switch change once.
Issue started last year.

 

[SJB060685]

Is this the down firing burner model?
In this nine months would you say after 9am you've been using HW more? Assuming I'm looking at the right flow chart (is several models of this boiler) then the wiring suggests that if the programmer isn't calling for HW you won't get a feed through stats and bring burner on.
Does the pump start circulating if you open a tap?
Also hard water needs to be treated, calcification occurs at higher temperatures which will reek havoc on systems

 

[SimonG]

Just re read original post. Wont get hot water after 9.00 in the morning when the hot water is off.
[automerge]1590600378[/automerge]

Is this the down firing burner model?
In this nine months would you say after 9am you've been using HW more? Assuming I'm looking at the right flow chart (is several models of this boiler) then the wiring suggests that if the programmer isn't calling for HW you won't get a feed through stats and bring burner on.
Does the pump start circulating if you open a tap?
Also hard water needs to be treated, calcification occurs at higher temperatures which will reek havoc on systems

For the age of the boiler I took it as the first green star heatslave. Crappy down firing with the pump at nearly the high point of the boiler. Had a lot of problems with the worcester built in clock.

 

[SJB060685]

When the heat store is up to temperature it will provide a certain amount of litres per minute at around 40°c temperature rise until the volume of the store has depleted all its stored energy. If that store does so there will be no HW until the programmer comes back on and reheats it, the flow switch just activates the pump.
One might argue in that case whats the point of the programmer. Well the idea of the programmer is to preheat the store before peak demands and prevent the on/off cycling found with constant switching, which in turn stops and starts the burner more frequently putting wear on components.
To answer your primary question, yes this can be fixed and could just be as simple as changing settings on programmer, alternatively there could be something else going on. I don't like combi boilers personally but providing the boiler has been well looked after up until now there is no reason you can't get more life out of it.

 

[bluesriff7]

the burner fitted is a riello RDB 1. one thing i have just remembered is that the engineer by passed the timer.
and i then i went in to the kitchen and turned the hot tap on. water cold and boiler did not fire up.

 

[SJB060685]

Ok then this is an electrical fault somewhere and needs a competent engineer to rectify. You said it was timed initially and now that's by passed so its hard to picture what the engineer has or hasn't done.

 

[bluesriff7]

The heating firm that installed my boiler are Bosch installers credit, but They sent out a young
person and he phoned Bosch support technical. Needs someone with more experience..
its due a service in august so I will phone round for some quotes.
thanks for all your help

 

[SJB060685]

If someone knows what they're doing they'll be able to look inside and figure it out. If there is link inside by passing timer then someone with a multimeter can check what voltages are where. This is basic stuff to be honest so any local oil engineer (not installer) should be able to help

 

[bluesriff7]

If someone knows what they're doing they'll be able to look inside and figure it out. If there is link inside by passing timer then someone with a multimeter can check what voltages are where. This is basic stuff to be honest so any local oil engineer (not installer) should be able to help

the engineer only used the link to see if the boiler fired up when i turned the hot tap on in the kitchen.
which it did not. link has been removed and i am back on the timer control now.

 

[SJB060685]

Are you competent with a multimeter? If the answer is no then no worries but you will need an engineer.