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Thread: New Gas boiler
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15-11-2019, 06:52 PM #1
New Gas boiler
I'm looking at adding a heat exchanger to my house central heating to heat my pond as it's a lot cheaper than electricity.
my current boiler is a potterton flamingo, it's 34 years old and not very efficient only out putting 8.8kW
stage one...
swapped out old boiler today for a worcester bosch 15 Ri 15 kw boiler.
thats a lot more efficient and should easily be able to handle the extra load from the pond.
oh, just in case anyone is interested... i got the boiler and installation, plus cavity wall insulation... for free!
stage two...
thats a bit more tricky...and will probaly take a bit more planning.
i need to route new pipework from the boiler primary's through the house, and downstairs to the outside wall. (boiler is upstairs at the opposite end of the house.)
and add a 3 channel controller, 3 port valve, and wiring to control it all.
though i'm wondering if i could use an aquatic digital temperature controller, as the extra 240v htg channel...
old nasty boiler out...
shiney new boiler in...
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Last edited by davethefish1; 15-11-2019 at 06:55 PM.
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15-11-2019, 07:27 PM #2
Am still on coal up here man Haha
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"we are water keepers first"
Johnathan
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15-11-2019, 07:40 PM #3
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15-11-2019, 07:47 PM #4
Wouldn't be paid to take it out like old Rayburn so got the door but still the best thing ever now it's getting so nasty outside
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"we are water keepers first"
Johnathan
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16-11-2019, 07:37 AM #5
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16-11-2019, 02:44 PM #6
Davethefish,
I heat my pond from the house gas heating. When changing my boiler I heard a load of difficult technical (and expensive) stuff that needed to be done to a combi boiler to make it work. So I stuck with the type of boiler that I had which simply heats the water and sends it through whichever zone control vale is open. I still have a cold water tank and hot water tank. I use a submersible stainless steel heating coil fed by quality 1/2" plastic piping which my heating engineer said was fine. The boiler is controlled by a thermostat in the pond. The pond thermostat basically sends 240 volts to the zone control valve which opens the valve and signals the boiler to start up. The zone control valve is close to the boiler.
A few things to factor in - 1. Automatic bleed valves on long runs of pipework to your pond, 2. A more powerful heating pump to push the hot water as far as the pond. 3. Plenty of isolation valves to enable you to switch off the flow and return pipes at various places. Including just above the pond water level at your heater.
Kenny
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16-11-2019, 03:27 PM #7
A few month ago I went to pick a uv up off a pond closure he had a house built over it like andikoi s and he had got a new boiler for house and rigged old boiler up in the koi house just for the pond so it was completely independent not sure how he sorted out gas supplies but was mint in there think it even had a radiator for the seating area
Sent from my SM-N950F using TapatalkFreddyboy the legend
"we are water keepers first"
Johnathan
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16-11-2019, 05:33 PM #8
Thanks handy kenny,
Mine is a conventional boiler (not combi) too.
I've seen some of the submersible coils and might decide to go that way,
or mount a heat exchanger to the back wall of the house and build an insulated housing around it and pipe the pond water to it.
i'm fine with the piped connections, been a pipefitter for over 30 years. commercial though, not domestic.
i'm trying to work out how to fit that into an existing 'Y' plan though.
i might have to change the 'Y' plan system to an 'S plus' plan to accomodate the extra zone,
or the house heating would come on at the same time as the pond at night...
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16-11-2019, 05:58 PM #9
This is on my list for the future. Specified extra capacity in the new boiler purposely for a heat exchanger.
I’ll be watching this thread with interest as I have absolutely no idea how it’s supposed to work lol.
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16-11-2019, 07:07 PM #10
Bigcarpchaser,
In concept it is really simple, a lot like adding a new radiator into your existing system and having an on/off valve (zone control) open and turn on the boiler when the thermostat in the pond detects that the pond needs heated. I got the thermostat and stainless steel heating coil (radiator) from Absolute Koi the rest is standard heating/plumbing stuff.
There are a few long runs of stuff like flow and return pipes to the pond from the boiler and a 240 cable from the thermostat to the zone control valve but still technically simple.
One thing I had to get my head around is where you actually heat the water. I am lucky enough to have a 2000 litre sump into which I put a wee blue barrel inside which is the heating coil and my pond pump. The pump sooks water in through holes at the bottom of the barrel, past the heating coil ( and loads of Serra Siporax for more filtration) up to the pump at the top of the barrel and out to the pond. In this way heated water is pumped directly to the pond and not wasted heating the sump.
Kenny
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16-11-2019, 07:20 PM #11
Davethefish1,
My existing system actually had two zones anyway, one for heating radiators and the other for heating hot water and storing it in the hot water tank. Adding another zone was actually a doddle and didn't take the heating engineer much time to hook it up. I had run all the cables and pipes.
I checked out a few ideas and came up what was for me the least expensive and quietest option. On cold nights (in Scotland) I have been woken by the gas boiler starting and going, and going, and going ........ One other thing I thought is that the chemicals and dirt in the pond water would contaminate a heat exchangers mechanism so really you would need a closed system with its own pump and in pond heat radiator on any heat exchanger system.
Kenny
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17-11-2019, 10:07 AM #12
Dave as you already suggested it would need to go to a
S plan plus. So a rejig at the airing cupboard.
Rather than a 3 channel programmer that's not cheap, keep the existing programmer for the heat and HW.
You could stick a cheap single channel programmer in the filter shed and run a cable back with the new pipes.
If it's a long run upsize the pipes. Worth also thinking about using an anti freeze inhibitor or wiring in a frost stat and pipe stat.
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17-11-2019, 01:38 PM #13
Simon Fish, Davethefish1,
I don't know about plan names but I am assuming my thermostat in the pond (Pro Digi-Stat Controller from Absolute Koi) is the same as a single channel programmer in that it controls the Zone Control valve and starts the boiler. Fitted in my greenhouse pump room it allows me to visually check the pond temperature and adjust the temperature that the controller sends the 240 volt signal to the Zone Control valve.
I used 1/2 inch Hep2O pipework, most of the rest of my heating in the house is microbore except for 1/2 inch to the livingroom for quick heat. The heating pipes and cable (240 mains) run in a 4 inch drain pipe (duct) fitted for the purpose. The 4" duct is as low in the ground as I could get it to keep it below the frost level and in Scotland that is lower than south of the border. The heating pipes in the duct are both surrounded by climaflex pipe insulation held in place by plastic straps. The heating pipes are around 10 metres from the boiler and it is a fair old run so at the ends where the pipes come out of the ground (into the greenhouse) I have fitted automatic bleed valves at the highest points. I considered using 20 mm pipework but the pipe and insulation would have been more difficult to install through the duct.
Since there is a long run on the heating pipes there is also a pressure release mechanism between the flow and return at the boiler end after the zone control valve. What this seems to do is allow a continuous flow of water through the boiler when the pressure of pushing the heated water (from a standing start after an idle period) through the pipework is too great. When closing the pressure relief valve manually the boiler intermittently throws errors on start-up so there is obviously some sensor in my new boiler that detects if water is flowing.
There is an argument for using a heat exchanger at the boiler end and sending cooler water along the external pipes which results in less heat loss but I discounted this for me partly due to the positioning of the boiler, heating pump and number of extra bits of kit required. In my head I calculated that the extra up-front cost was perhaps not worth it.
Kenny
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17-11-2019, 03:14 PM #14
The plan names just relate to different ways of configuring heating and hot water systems.
So the S plan plus is 3, 2 port valves.
A 2 port valve is very simple to work with and can be wired to suit what you need, so just to open or also to send power on when open.
They are usually NC normally closed but also come NO normally open, so the options are to configure a system that does whatever you want, within reason!
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17-11-2019, 05:59 PM #15
thanks i hadn't considered the boiler noise.
the old boiler, being balanced flue was virtually silent in running.
but the new boilers flue fan can be heard at night, it's very quiet, but just about audible.
that might be my biggest hurdle....if the missus can hear it running at night.
might need to soundproof the boiler cupboardLast edited by davethefish1; 17-11-2019 at 06:12 PM.
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17-11-2019, 06:10 PM #16
good call with the single channel thanks,
thinking about the wiring...
as the filter house power is on a separate circuit, i'd need to run a live and neutral from the controller back to the 2 port valve to open the valve
but should be able to use the control junction box live for the 2 port valves 240v boiler power feed?
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17-11-2019, 08:23 PM #17
The danger with having electric connections at different ends of the house is the temptation to take a power supply from what's closest. This then leave a danger when it comes to future work and thinking something is isolated.
I would take the power from the airing cupboard wiring centre, just send a cable with enough cores to do what you need.
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17-11-2019, 10:59 PM #18
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18-11-2019, 12:59 PM #19
Just as a side note folks,
Has anyone installed a separate LPG boiler for their pond?
I currently run an ASHP as we also have PV, so great in the Spring & Summer but not so efficient in Winter. Gas seems to be the way to go but don't want to tie the house system into the pond heating.
The only thing I'm a bit unsure of is the flue configuration as we have a single storey school building behind us which is only about 2m from my filter room.
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18-11-2019, 06:15 PM #20
The distance of the flue to the boundary is what matters.
Usually 600mm but can vary depending on manufacturer and other factors.
Get someone to have a look.
Go on gas safe register, do a postcode search looking for an engineer, and put LPG in the requirements.
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freddyboy Thanked / Liked this Post
Aquaforte Dm vario 20000 pumps
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