plant room upgrade

when I started this project it was going to be run from the existing bmu but the customer wanted it to be simple to operate. when we explained the fantastic controls that comes standard with the v200 the customer asked us to integrate weather compensation and run directly from the v200 controls. the low loss header is not suitable for this purpose and originally I intended to strip it out and fit the v i e s s m a n n header. to simplify things further I could separate the two boilers, using one boiler to run the underfloor heating system via a low loss head and the other to directly supply the radiator circuit. is then occurred to me that I didn't need to remove the existing header if it was to only support one boiler. it's a touch on the big side for a single boiler but on the other hand it saves a lot of work leaving it in. so the job is now weather compensation fitted but running at high temperature to avoid issues with the buffer. we're waiting for the signed order to carry out the rest of the work and have a professional date for 2 weeks time. I will post a video on the completed job as long as it is authorised in the next couple of weeks

[@CommercialGasEngineerVideos]

Good job Andy, let me quote for the lagging. You the man. Keep up the good work.

[@normanboyes4983]

The customer will be really chuffed with this new transplant, much easier to control. Why have you got flow control valves on the cylinders? Does Viessman not have the native capability to control on two cylinders?

[@andrewmillwardwatford9410]

The zone valve are required to comply with G3 as the cylinders are not manufactured by v i e s s m a

[@ununha]

Are they 4 pipes heat only boiler? One side for heating and one for hot water?

[@andrewmillwardwatford9410]

Yes the boiler has its own diverter valve on the flow side of the boiler

[@alexbennett8437]

What are you using to activate the 2 port valves on the cylinders?

[@andrewmillwardwatford9410]

Well originally I thought I was being smart and that by using an emp1 extension that I would get a hot water loading signal. Now I think I was wrong. I'm back on this job in 10 days time so I'm looking for a new strategy

[@alexbennett8437]

@@andrewmillwardwatford9410 if you have to have the valves then i have a solution for you. What i would do is when the cylinder calls for heat, the valve activates a simple relay which makes the connection on the cylinder sensor. and when the valve is not power the relay reverts to its default position which goes through a resistor which tricks the boiler into thinking the hot water is satisfied.

[@alexbennett8437]

do you have to have 2 port valves? i normally just wire the cylinder sensor through the overheat stat, so if it ever overheated (which it wont) it would disconnect the sensor which would stop the boiler from firing in hot water mode. heating would still work

[@andrewmillwardwatford9410]

@@cliveramsbotty6077 they are. Although at the moment I don't have the correct signal it is passing through the overhead stats. I have temperature control on both cylinders via cylinder sensors but I have linked both hydraulic lead to both boilers so there is some small discrepancy in temperature control. I need to find a solution for this problem in time for my return in 2 weeks time

[@hufartd]

@@alexbennett8437 I’ve done it by wiring the boiler via the overheat stat which just kills everything. Super safety and all that.