Please review the design

lesnick · Posted: Sat Jan 07, 2012 5:00 pm

I tried to draw water and CH supply inluding all elements. There are pleanty diagrams in the network, however most of the don't show valves and cocks.

Please advise if anything missing or placed wrongly. I was trying to use correct symbols, but could not find all.

Any advice appreciated.

swbjackson · Posted: Sat Jan 07, 2012 5:20 pm

The radiators in the areas where the room stats are fitted should not have TRVs fitted.

Dan_Robinson · Posted: Sat Jan 07, 2012 5:23 pm

You forgot the dishwasher.

flameport · Posted: Sat Jan 07, 2012 5:29 pm

Boiler will require another pipe for the safety valve outlet, and a drain point below the boiler would be useful so that parts can be replaced without having to drain down the rest of the system.

Loft needs to be suitable for the boiler to be installed - i.e. solid floor, lighting and a ladder to get up there.

I wouldn't fit wireless thermostats on a new installation.

lesnick · Posted: Sat Jan 07, 2012 10:27 pm

Any specific reason for avoiding wireless?

The idea is to use Honeywell CM927 which can be moved between bedrooms if required. When it's taken into to the room the thermostatic valve would be fully open.
On ground floor mainly to avoid wiring.

Unfortunately, the kitchen is not big enough for the dishwasher. The plan is to extend it and that is the reason not to install the boiler there.

Would the relief valve be connected to the drain which is used for condensate pipe?

Thanks for your comments.

holty · Posted: Sat Jan 07, 2012 10:33 pm

why don't you give the plans to the company who is going to install the boiler and see what they say?

lesnick · Posted: Sat Jan 07, 2012 10:44 pm

holty wrote:

why don't you give the plans to the company who is going to install the boiler and see what they say?

Will do indeed, however always good to have several professional opinions.

flameport · Posted: Sat Jan 07, 2012 10:47 pm

lesnick wrote:

Any specific reason for avoiding wireless?

The idea is to use Honeywell CM927 which can be moved between bedrooms if required.

Wireless thermostats are intended for installations where it is not practical or desirable to install wiring, such as when replacing an existing poorly sited thermostat, or installing one where there wasn't one before.
They are NOT intended to be moved around the house. They are installed to control the whole zone, not individual rooms - that's what TRVs are for. That is also why the thermostat needs to be in a room where the radiator doesn't have a TRV (as already pointed out by swbjackson).

As the installation of the new radiators will obviously involve lifting floorboards and drilling holes etc. for the pipes, it's hardly any extra work to put a cable or two in at the same time.

The other reason it that wireless has far more to go wrong - batteries require replacement, the receiver and stat need to be paired (and this can go wrong after installation so may need to be done again), they can be affected by radio interference from other equipment, and may not work well or at all if there are substantial structures between the receiver and stat.

Another common blunder is people installing a battery powered wired thermostat to a system which uses mains voltage switching.

hansthebear · Posted: Sun Jan 08, 2012 12:49 pm

no need to valve the hot water outlet from the boiler

DeltaT2 · Posted: Sun Jan 08, 2012 1:16 pm

Never mind the design Les, what software did you use to do the design??

lesnick · Posted: Sun Jan 08, 2012 9:56 pm

I have updated the diagram with the most changes proposed here:

-) TRVs removed in the room with the thermostats
-) Valve removed from hot water outlet
-) Drain valve added to the CH flow at the lowest point

Question: As the boiler is at the highest point of the system can it be drained by draining few liters from the lowest drain valves?

-) Drainage pipework are added to the diagram
-) Relief pipework is added assuming the relive valve is part of the boiler.(used WB 30CDi installation guide). Not sure though if it can be done such way at the loft level.

Kept wireless for now, but will do further study and consider using wired.

The diagram was drawn in MS Visio software (use it regular in my telecom/IT engineering job)

flameport · Posted: Sun Jan 08, 2012 10:14 pm

lesnick wrote:

-) Relief pipework is added assuming the relive valve is part of the boiler.(used WB 30CDi installation guide). Not sure though if it can be done such way at the loft level.

It can't - it will need to be taken to an outside drain at/near ground level.

If the valve operates while the boiler is heating, boiling hot water will be forced out of the pipe.

Dan_Robinson · Posted: Sun Jan 08, 2012 10:17 pm

It can as long as the pipe is pointed back against the wall.

lesnick · Posted: Sun Jan 08, 2012 10:50 pm

Dan_Robinson wrote:

It can as long as the pipe is pointed back against the wall.

Updated the diagram accordently.

lesnick · Posted: Sun Jan 08, 2012 11:11 pm

In WB 30CDi installation guide I have noticed:

Quote:

Where the system volume is more than 100 liters or exceeds 2.65 bar at maximum heating temperature an extra expansion vessel must be fitted as close as possible to the appliance in the central heating return.

I wonder how would you practically measure that. By pure estimate calculation or filling in the system and draining and measuring?

How much water 7-8 radiators CH system in 3-bed semi would normally use? Anywere close to 100 liters or it's not my case?

Thanks