New boiler help! PigletJohn are you available pretty please

[Ziopin47]

Hello guys, I need your help in choosing a new boiler.

Recently moved into a 200 year old cottage, with an ancient boiler (fitted in 1961!) it's one of those that you have to turn the water on 3 hours before your lukewarm bath is ready 😜

The house is detached, with 4 bedrooms, 2 bathrooms (1 with a bath) and a separate en suite (electric shower)

Water flow is not great. I also have radiators probably from the 60's throughout the entire house (which I quite like and wouldn't mind keeping)

I've had a couple of plumbers around to give me a quote and they have both suggested combi boilers, but I don't think this would work in my property.

I am having my main bathroom renovated at the end of next month to have a bath and walk in shower and am hoping to change the electric shower to a non-electrical one in the en-suite.

I have a big water tank in the airing cupboard and a cold water tank in the attic.

Any suggestion would be greatly appreciated.

Thanks x

So I have a very similar house, bathroom, old boiler setup. We are extending (though not increasing bathroom numbers) and the (30 year old Camry 5) boiler is in the way.

We are installing an external boiler. First plumber specced Grant eco vortex, but current heating engineer (also a friend) has just delivered a Navien.

It is a system boiler which means the tanks in the loft are no longer required. We we are also replacing our hot water tank (current one is 130l and won't be big enough when we convert the electric shower). We are installing a 250l indirect unvented Megaflo tank.

An unvented water tank will give you hot water at the same pressure as your incoming cold water. But if your cold water pressure is pants then it won't work (think there is a mimimum of 2 bar but am ready to be corrected by PigletJohn).

Ours is pants, not sure what the current pressure is but flow is 8l/min. Its a private supply so we are installing a 600l tank and a DAB e.sybox pump.

If you are on mains water then I think I've seen PigletJohn suggest that you can fairly easily increase your pressure by increasing the size of pipe into the house?

If that setup doesn't give us me an amazing shower then there may be some plumbers found under my foundations in later years.

I looked at combi and could see the benefits but I think if 2 people might want to shower at similar times then its a no go.

Thanks for your reply

It's a bit of a head scratcher tbh, it's a pricey bit of kit to get wrong isn't it? X

What colour is your hot water cylinder?

Is it a gas boiler?

How many water tanks are in your loft, and what size are they? How deep is the mud in the bottom?

Is your water from the main?

Fill a bucket from the cold tap. Time it. Calculate litres per minute.

If you have an outdoor tap, try that too. How many lpm?

Good morning PigletJohn! Thank you for responding to my call for help

I will get up that attic and test the water pressure this afternoon and get the information to you. Thanks again x

Ok, so litres per minute is just under 8 on both kitchen and outdoor tap.

From what I can see, there is one big cold water tank in the attic, but I can't access it due to roof height, to look at the mud.

I have attached a photo of the gas boiler and green hot water tank.

Should also mention there are 3 adults living in the house, so not a huge need for people to be bathing/showering at the same time.

Thanks John x

Hurray for PigletJohn! It's because of his wise words that we didn't shell out nearly £2k on a fancy extractor in the kitchen. "Pretty, but useless" was roughly what he said.

Like I say, very wise.

(Sorry for derailing!)

(Assuming PJ is male of course )

8lpm is very poor, and not enough for a decent combi or an unvented cylinder, or a satisfactory shower.

I think that as well as the big water tank in your loft, you also have a small one, about 18 inches long x 1ft x 1ft. This is very important and probably very muddy. Which is very undesirable. Please try to find it.

Your hot water cylinder is what I would call yellow, so about 30 years old. It is slower to heat than a modern cylinder.

Do you have to turn off your radiators individually in summer, at their valve knobs? I think the HW circulation is by gravity (thermosyphon) but it might be that the pump circulates radiators and cylinder at the same time. This can be fixed fairly easily. Your old plumbing is doubtless full of sludge and sediment, so I recommend having a Magnaclean or similar fitted, now, the next time you have a plumber in. I think you need the 28mm size, which is bigger than usual and may need to be ordered.

First, look at your incoming watermain, at the indoor stopcock (probably under the sink) and the outdoor one (probably by the front gate). It might be lead, iron, copper, black plastic, or blue plastic. Decide if it is at fat as your finger or as fat as a banana, and what it is made of. Do you have a water meter? Is it in the public pavement?

You could speed up your HW heating by (greatest improvement first) converting it to fully pumped, with a cylinder thermostat. Then changing to a more modern cylinder (probably bigger), then adding a timer to control cylinder heating. Better, do all that, at the same time. It will work even if you don't change the boiler yet. If your boiler works you can change it if and when you feel like it, or it breaks and parts are unobtainable. Your new boiler will be about a quarter the size of your old one. You haven't mentioned a reason to change it.

You could improve HW best of all by changing to an unvented cylinder, but it would need to be fully pumped, and you would need twice the incoming water flow. Most likely by digging a trench and laying a new, bigger, plastic water pipe. It is not as difficult or expensive as you think. But plumbers are weedy little fellows with petal-soft hands, frightened of spades, so the trench is usually dug by a burly woman fond of gardening, or a builders labourer.

Insulate all your water pipes, too.

Wow! Thanks for your detailed advice. Yes, I need the boiler replaced as having a kitchen extension starting in August, so the old one will need to be removed before the refurb and a new one located, preferably in the airing cupboard where the hot water cylinder currently lives.

Yes, the rads upstairs come on when the boiler is heating the water, so do need to turn them off in the summer months.

I don't have a water meter it comes straight from the mains via the pavement I think.

I can't find the outdoor stopcock but the one under the sink is the width of my finger.

I suppose my main priority it to have a toasty house and hot water on demand 😬

Thanks lovely x

plumbers are weedy little fellows with petal-soft hands, frightened of spades, so the trench is usually dug by a burly woman fond of gardening

I love you PigletJohn. I'm having a crap day and you've mad me laugh.

Good luck, OP - I suggest you might need a Plumber of a certain vintage iyswim.

"I can't find the outdoor stopcock but the one under the sink is the width of my finger. "

that's a pity.

Copper, i expect.

The new one does not have to follow the same route, it can go by wjhatever's easiest/shortests/straightest line from the connection in the pavement.

If you have wooden floors with a gap under them, you can enter the void underground, and run it under the floor. pipes can also be run under the first floor, or in the loft.

if you have concrete floors it will probably be easier to run it along the side of the house (assuming your kitchen is at the back). if you're having building work done you might be thinking about making changes here anyway (including replacing any leaking drains) or prhaps lowering levels that have risen to the DPC.

It is also possible to put a pipe through a moled tunnel. Some plumbing contractors have special moles for this job.