New central heating and type of boiler needed

[Dins]

I have recently move into an average 4 bedroom property (with a single bathroom upstairs). Current boiler is a Combi, which is not working (ferrolli boiler, which was not great the 3 months it did work, only 4 years old) and the house has 11 radiators.
I plan to divide the bathroom into 2 separate rooms, each having a shower and 1 with a bath. I'm unsure which type of boiler / system to get. The water flow is not great (16 litres per minute). My concern is that I will not be able to run both showers at the same time. I have had a few central heating engineers around but the majority want to stick a Combi boiler in. Any advice and experience would be appreciated.

 

[hammers4spanner]

urrrgh combi monkeys

 

[Masood]

A combi won't cope well with two outlets at the same time, especially with only 16l/min. Have you had your incoming mains looked at? Could be an old lead pipe. Replacing it with MDPE would help. Beyond that you're looking at a break tank and booster set or an accumulator...

 

[Dins]

Yes, no body wants to fit anything else, I was thinking more a system boiler (I'm no expert that's why I need some advice) but seems like no one wants to fit one when mentioned. Has anyone had experience with fitting a Worcester Highflow 440 CDI boilers, would this work?

 

[julesverne]

The best solution for you would be an unvented cylinder and system boiler. But there are a lot of ifs and buts. Firstly you need the incoming mains pressure tested and like masoods says it may need upgrading to mdpe.
Worcester high flow arent the best solutions either as once the store runs out its just like a combi.

Either way it will cost more than a combi a lot more. So maybe this is why a combi was installed inthe first place. If you want it doing properly it will cost you nearly twice the price of a combi install if not more.

 

[julesverne]

If you post your location a more experienced installer from th forum may be ablemto help

 

[IDCHAPPY]

I'm not sure to be honest, 16l/m will do for a large combi and supply 2 outlets at the same time, unventeds usually require 20l/m flow ratewith 1.5 bar inlet pressure.

 

[IDCHAPPY]

2 baths will toil yes, but most normal shower heads use 8/9 l/m. What's the usage like? How many people are in the property?
I'm changing a system and unvented to a combi next week as the lady is mid 70s and lives on her own, there'sno need for her to heat 250l of water to wash her hands so I'm specing the boiler to the client and not the property.

 

[Ray Stafford]

If you are sure about the 16 litres per minute, and assuming that you have usable loft space, I think the best solution is to go traditional. Combis are rubbish at multi-outlet, and 16 ltrs/min is too little for unvented.

Store cold water in the loft, (at least 50 gall, preferably 75 or 100 gall). Vented cylinder - probably 1500mm x 450mm or larger - and either a heat-only boiler or a system boiler, on the CH side, it really doesn't matter.

You may need to fit a decent shower pump (look at Stuart Turner Monsoon or Salamander CT Force Brass) to get decent shower performance, but that cost will not be appreciably more than the difference between unvented and vented.

OK, you won't have the most modern design in your street, but its tried and tested, and will work admirably on multiple outlets.

The other possibility is to look at upgrading the incoming main. If you could get decent working pressure at a flowrate in the mid twenties ltrs/min or better, I would change my advice to fitting unvented.

The Highflow boilers are not the solution with that limited flowrate.

 

[hammers4spanner]

In all fairness to the OP needs to look at his/her budget as some replies here are unfortunately going to cost a fair whack of money.

 

[Geyser]

Some plumbers haven't got a clue about systems outside of combis and spec them regardless of needs. Combi definitely not the best system for you, but if bugdet and space is limited then a good combi well installed with flow limiters on outlets and even an awareness of who's in the shower or running a bath when, it iis posible. In my own six bed house with two bathrooms we manage ok with a combi.

 

[stevetheplumber]

whilst i agree that a combi isnt always the answer working with what this customer has it will probably be the best bang for his buck all the other solutions are going to beat least twice the price any form of cylinder will require the space unless it goes in the loft if there is room in a modern 4 bed property. you will get showers from a combi if you use reduced flow heads or as most families do learn to stagger their showers

 

[IND_Nick]

Once a combi has been installed in a property I often find it difficult converting back to a stored hot water system, unless there is plenty of space in a garage, loft or utility. People tend to lose airing cupboards, rip out excess pipe work and then put laminate or hard wood flooring down throughout! With 16l/m I would look at the high end combi options or consider replacing mains, if possible or as someone else said storage and accumulator but this is where costs could rocket. Find a local plumber you get on with and discuss the options, expressing your concerns and see what they say.

 

[Dins]

Thanks for info. I was just wondering would a plumber normally check the water pressure with a tool before giving any advice on fitting a new boiler? I've had 5 plumbers round and only one has checked the water pressure.

 

[Rckape]

I can't say I check on every job. But in the case of your job, I would check the flow and pressure to either recommend or rule out different systems. Notably an unvented system.

 

[Worcester]

Would a plumber normally check the water pressure with a tool before giving any advice on fitting a new boiler?

Plumbers wouldn't, heating engineers would - especially after discussing your requirements with you.
Combi bashers wouldn't even know HOW to measure the pressure properly.

 

[rpm]

Plumbers wouldn't, heating engineers would - especially after discussing your requirements with you.
Combi bashers wouldn't even know HOW to measure the pressure properly.

Are you saying ALL plumbers wouldn`t?
Sounds like a dangerous statement to make to me!

 

[rpm]

2 baths will toil yes, but most normal shower heads use 8/9 l/m. What's the usage like?

Dunno about you guys but I`m coming across a lot of power showers kicking out +15 l/m

 

[Worcester]

Are you saying ALL plumbers wouldn`t?
Sounds like a dangerous statement to make to me!

Nope, just that we see too many systems where plumbers that have no fundamental understanding of heating have installed heating systems that work so inefficiently that they should restrict themselves to the hot cold and waste. The is a major difference between plumbing and heating.


The OP's experience says it all, only ONE out of 5 bothered to check the flow and pressure.

Geyser's post said a similar thing

Some plumbers haven't got a clue about systems outside of combis and spec them regardless of needs.

We see that all the time.

As an example, a simple Question - how many here know how to create a heating package ERP label and fiche? - after 26th September you'll have to.

 

[SimonG]

There will be an app for that by then Worcester