Condensing boiler with hot water tank?!

BigAunty

Thanks for the advice.

The problem with the variable water in the kitchen hot tap turned out to be an issue with the tap itself, not the cylinder or water pressure.

In the process of having a wireless thermostat/timer installed. However, the Worcester Bosch timer recommended by WB themselves for their Greenstar range can't be installed as the boiler requires a new diverter valve for it to operate.

We only discovered this after stripping out the wired thermostat and timer (so the heating and hot water has to be controlled manually). The engineer is contacting WB for advice and researching other wireless timers products suitable for system boilers (covering both water and heating).

The plumber noted from the previous owner's paperwork that their gas engineer provided them with a quote for a Greenstar 30 cdi but then installed a 40 instead which is perhaps why a 3 bed/1 bath house has a boiler more suited to a much larger property.

He believes the water cylinder predates the boiler installation so the previous owners probably just decided to keep it rather than having a condensing boiler with instant hot water or as a backup to have hot water even if the boiler fails. I really don't like this set-up at all but I'm not going to replace it.

malc_b

You should have a label on you HW cylinder. I fitted a foam insulated one in 2004 and it had a label. This says 140 l, loss over 24hrs = 2.51kWh. In other words if you use no hot water but just keep it hot it will use 2.5 kWh, about 30p on full rate electric or 15p on gas. There is no need to have instant hot water combi boilers since the saving in minimal (also the heat is only wasted in the summer, the other 6-9 months it heats the house). The other point about combi vs HW cylinder is the flow from a HW cylinder is far higher so you can run baths faster or have showers with a good flow.

captainhindsight_2

More and more people are switching back to having hot water tanks, as it means you can easily take advantage of different technologies in one heating system thus saving money.

BigAunty

captainhindsight wrote: »

More and more people are switching back to having hot water tanks, as it means you can easily take advantage of different technologies in one heating system thus saving money.

I understand why a householder who has always had a cylinder may retain it when they upgrade their boiler, the advantage of having hot water even if the boiler breaks down and that it is a good method of having plenty of hot water in a big house (which mine isn't...).

But I still don't like the arrangement one bit.

Finding a wireless timer/thermostat for it has been a total pain. There's plenty of choice if the boiler is a traditional combi or condensing boiler but very limited for those with a cylinder (system boiler) which requires separate settings for water and heating.

My electrician stripped off my wired thermostat and installed the new WB one (recommended by WB themselves when I enquired) and then found it doesn't suit my boiler after all. I will now have to sell that now used £150 thermostat second hand on ebay to try and recoup my money.

My hallway where the traditional wired thermostat is located is drafty so I wanted to be able to have one which I can place in a different room to get a more accurate reading of when the house is at the right temp. I also wanted it to work with a smart app so I can control the heating through my phone as I will start shift work soon.

I then got a recommendation for a Honeywell wireless timer (Sundial) and that could cost up to £250! (depends on what type of pack I require). In comparison, there is a raft of wireless thermostats/timers for more conventional boilers for £50.

So as well as higher general bills which I think comes from the power required to heat a tank of water (though i will adopt the strategies recommended here to put it on for longer), basic things like a thermostat cost at least 3 times (and possibly up to 5 times) more.

captainhindsight_2

BigAunty wrote: »

I understand why a householder who has always had a cylinder may retain it when they upgrade their boiler, the advantage of having hot water even if the boiler breaks down and that it is a good method of having plenty of hot water in a big house (which mine isn't...).

But I still don't like the arrangement one bit.

Finding a wireless timer/thermostat for it has been a total pain. There's plenty of choice if the boiler is a traditional combi or condensing boiler but very limited for those with a cylinder (system boiler) which requires separate settings for water and heating.

My electrician stripped off my wired thermostat and installed the new WB one (recommended by WB themselves when I enquired) and then found it doesn't suit my boiler after all. I will now have to sell that now used £150 thermostat second hand on ebay to try and recoup my money.

My hallway where the traditional wired thermostat is located is drafty so I wanted to be able to have one which I can place in a different room to get a more accurate reading of when the house is at the right temp. I also wanted it to work with a smart app so I can control the heating through my phone as I will start shift work soon.

I then got a recommendation for a Honeywell wireless timer (Sundial) and that could cost up to £250! (depends on what type of pack I require). In comparison, there is a raft of wireless thermostats/timers for more conventional boilers for £50.

So as well as higher general bills which I think comes from the power required to heat a tank of water (though i will adopt the strategies recommended here to put it on for longer), basic things like a thermostat cost at least 3 times (and possibly up to 5 times) more.

Combi Boilers are only really suitable for smaller houses. It sounds like you have just had bad advice because no one would fit a combi where there is more than one bathroom and there are a lot of houses with more tthanone bathroom and all should have a system not a combination

bob_a_builder

Not sure why you want a wireless programmer/thermostat
That seems to be complicating things
Assume there is/was already some sort of programmer ( i.e timer ) for both heat and water

Surely its only the themostat part you need to be wireless, since you want to move it from hall to lounge
you don't need to program CH & HW timings from lounge - do you ?

although having said that a lot of the modern thermostats allow you to set 4 or 5 different CH temperatures during a 24 hr period - in which case main programmer can be set just to come on once- say 06:00 - 23:00 and

jennifernil

BigAunty wrote: »

I understand why a householder who has always had a cylinder may retain it when they upgrade their boiler, the advantage of having hot water even if the boiler breaks down and that it is a good method of having plenty of hot water in a big house (which mine isn't...).

But I still don't like the arrangement one bit.

Finding a wireless timer/thermostat for it has been a total pain. There's plenty of choice if the boiler is a traditional combi or condensing boiler but very limited for those with a cylinder (system boiler) which requires separate settings for water and heating.

You are a bit confused.

There are combi boilers and condensing combi boilers.

Then there are system boilers (which I would call "traditional") and condensing system boilers.

All new boilers must be "condensing" unless there is a good (documented) reason why one cannot be fitted.

The total lack of HW when a combi breaks down is the main reason I would never have one. Plus the fact there is more to go wrong with them.

We replaced our controller a couple of years back, there seemed to be plenty of choice, but we did not go for anything complicated like you want.

For separate control of heating and HW you either need 2 pumps or a 3-way motorised valve.

fezster

BigAunty wrote: »

Thanks for the advice.

The problem with the variable water in the kitchen hot tap turned out to be an issue with the tap itself, not the cylinder or water pressure.

In the process of having a wireless thermostat/timer installed. However, the Worcester Bosch timer recommended by WB themselves for their Greenstar range can't be installed as the boiler requires a new diverter valve for it to operate.

We only discovered this after stripping out the wired thermostat and timer (so the heating and hot water has to be controlled manually). The engineer is contacting WB for advice and researching other wireless timers products suitable for system boilers (covering both water and heating).

The plumber noted from the previous owner's paperwork that their gas engineer provided them with a quote for a Greenstar 30 cdi but then installed a 40 instead which is perhaps why a 3 bed/1 bath house has a boiler more suited to a much larger property.

He believes the water cylinder predates the boiler installation so the previous owners probably just decided to keep it rather than having a condensing boiler with instant hot water or as a backup to have hot water even if the boiler fails. I really don't like this set-up at all but I'm not going to replace it.

I dont know too much about WB boilers, as I have a vaillant. However, if it's a traditional boiler (non-combi - doesnt matter if it's condensing or non-condensing, as this is about efficiency), then it should allow a programmer to be wired up. This would normally be used to control the timings the heating and hot water come on, operating zone valves in the process to the 2 different circuits. The programmer then allows a thermostat to be wired up. This usually consists of just 2 wires. You can then wire up a wired thermostat, or a wireless thermostat, the only difference being that the wireless has a control panel which can be detached from the main unit, sending the signal wirelessly to it. The thermostat can be programmable or non-programmable. If it's programmable, you would leave your main boiler programmer to have the heating "on" all of the time, but in actual fact it would only come on when the thermostat calls for heat.

I would think you can use any wireless programmable thermostat, not sure why you're constrained. The main thing is to ensure you have a decent programmer installed and working, the thermostat is then easy enough to wire up to it.

Sorry if Im missing something significantly different in your system. Im sure your plumber is competent, but just in case, might be worth getting a second opinion, as this shouldnt be that complicated. It's worth keeping in mind that most plumbers / gas safe engineers are not electricians, so may not be as well versed in fitting programmers and thermostats.

I_have_spoken

I had a house with basic open-flue boiler, then h/w tank and C/H circuits with a CH/HW programmer and 3-way valve.

To make it work with my programmable roomstat (Drayton Digistat 3), I just set the CH on the programmer to be always 'On', then fed the call-for-heat from the Drayton's receiver into the wiring block, replacing the wire from old thermostat.

That way the Drayton took 100% control of CH timing/temp and the Programmer just relayed the signal to fire the boiler/pump and move 3-way valve as needed. I left the HW to the programmer, it ran the boiler for 40 mins 1st thing to heat enough water for showers. Of course there was also a thermostat strapped around the HW tank to prevent it getting too hot regardless of the Programmer settings


My current house was converted to full combi by previous owners so the hall airing-cupboard is now just storage - although they left me to remove the header and expansion tanks from loft, plus overflow pipes running into the eaves! They actually put the combi in the attached garage, so it's inaudible in the house. A bit odd when for years I was used to the 'whump' of an open-flue boiler firing.

Better_Days

OP would one of these wireless programmable thermostats suit you - they can be controlled via a smartphone or online?
http://www.amazon.co.uk/SALUS-IT500-Internet-Controlled-Thermostat/dp/B00FKRS514/ref=sr_1_1?ie=UTF8&qid=1417277194&sr=8-1&keywords=salus+it500

Lots of good reviews and positive feedback about customer service helpline. Great if you work irregular hours (or if like me you need to upgrade anyway, and like the idea of controlling the CH from bed!)

As I said above I have a old floor standing boiler and gravity HW tank. I had a heating engineer round last week and he is going to fit a valve so we can control the HW separately from the CH. He is also going to fit the Salus IT500 programmer and wireless thermostat for me.