commercial heating sysyem.

[REDSAW]

dont normally do stuff on this scale.
but today we installed 40 trv's in an office.
came to fill up and we cannot get the heat through. initially it had an air lock and we ran it of through the drain offs which seemed to work for a while and then went cold again.
checks were made for venting of even in the roof voids, there is water flow at all pumps and the boiler is running.
there is 3 pump circuits, and one of them we cannot figure out what it is?. but is also running.

is there a logical sequence for kicking this system into gear, or have we missed something?.
any ideas?.

 

[WHPES]

Have you tried running one pump and one rad at a time as you do to blow airlocks out?

The third pump may be a separate zone but on the same floor? Perhaps just serve the common areas?

 

[REDSAW]

Have you tried running one pump and one rad at a time as you do to blow airlocks out?

The third pump may be a separate zone but on the same floor? Perhaps just serve the common areas?

well i did ask my gaffa (you know, the one that takes all the crp when it all goes wrong-mate, cos its his job.lol) if it was worth doing that annd he said 'what with 40 rads?', but he did make a point that not one rad was getting warm, not even the first radd next the plant room.
the third pump had something like bur? pump on it, its the middle one in photo.

 

[WHPES]

Are two of the pumps parallell to each other on the same circuit? In large systems this is common - one is a backup pump to the other (you are supposed to switch them over each time and open / close respective pump valves when the system is serviced to prevent them seizing up).

 

[REDSAW]

hmm, personally i think your on the right track.
in the picture, the top circulator, pumps downstairs. the pipe below the bottom circulator is the up/return. which is 't' into the middle bur? pump via 3 port zone valve. this is 't'd into bottom pump line.
the control board has 3 pump switches and all 3 are on till morning.
the pipes either side of the pumps are hot, but i have a thought they are just spinning a short loop as you say.
i thought about switching of the mid-circulator, but i dont get a say although he's a lot more experienced than me as i am his pig.lol.

 

[Puddle]

Probably the centre pump keeps water in boiler hot via valve to on right,others could be one back up or to increase flow as demand requires
Anyway few thing to try
1.Should have turned boiler down and left running over night
2.40 valves but thermostatic so not long to close down and restrict flow round circuit
3.Isolate middle pump electrically and on gate valve,as if in boiler heat mode will be reducing other pumps pressure back to boiler
4.See auto fill,let over ride and let fill to higher pressure equivalent to hot pressure,if clears reduce
5.If near rads not getting hot ,blockage local ,try turning one pump around,isolating others to reverse circulation
6.Ring Shaun

Were is the vent for top pump or does pipe work go up would have been good to see pipe work behind boiler
If you have left running ,bet will be all circulating ok in the morning

 

[REDSAW]

Probably the centre pump keeps water in boiler hot via valve to on right,others could be one back up or to increase flow as demand requires
Anyway few thing to try
1.Should have turned boiler down and left running over night
2.40 valves but thermostatic so not long to close down and restrict flow round circuit
3.Isolate middle pump electrically and on gate valve,as if in boiler heat mode will be reducing other pumps pressure back to boiler
4.See auto fill,let over ride and let fill to higher pressure equivalent to hot pressure,if clears reduce
5.If near rads not getting hot ,blockage local ,try turning one pump around,isolating others to reverse circulation
6.Ring Shaun

hmmm, where do i start?. 6, sounds best. just dropped his number on my phone
1, boiler has been left on till morning.
2, should have at least one rad hot though?.
3 will take a look at that one.
4, sure we done that allready.
5, f..it, he can do that one.lol
ta 'p'

 

[Puddle]

see you left coffee on boiler to keep warm for the morning

Were is auto fill connected ?,can we isolate flow and return one at a time and flush through further down the line?

 

[REDSAW]

yeh, disgusting init?. had to actually pay for me own drinks today @ 20p a cup.
tight sods.

 

[migoplumber]

not totally clear, but looks like one constant temperature circuit (maybe to rads)
one is a variable temperature circuit, the othe looks like indirect cylinder feed.
forget cylinder for now
forget 40 rads for now
concentrate on the vt circuit, flow through pump and directly through 3 way valve into boiler return giving you boiler short cycling
manually open 3 port valve (this system will require removal of actuator head and screwdriver insertion ! this should send heat into vt circuit which could well be rad circuit (optimized if your unlucky)
once youve discovered which circuit the vt controls then you can balance the primaries (still forgetting 40 rads)
once primary is balanced then shut other 2 'zones' and balance your 40 rads as normal.give me a bell if you get stuck !

out of interest what controls the actuator ? gotta be a control panel of some sorts, open it up and have a look inside before belling me. dont need to tell you to be carefull in there !!

 

[REDSAW]

there is a filling loop to the right of the header on bottom pipe.
we did that tho, stuck the hose on 4 drain cocks down stairs and ran till hot, then went cold again?.
although i was the leg man, up n down, up n down. i used to be 6' before today.
my m8 was in the boiler room relaying me.

 

[stevetheplumber]

why is there a filling loop to me that looks like a pump set to fill it from

 

[migoplumber]

manually filling loop is okay, but regs say you must have auto fill up device for anything over 800 (ish cant remember exact) litres in primary. dosnt matter how you fill it tho !! just too be picky expansion vessel looks undersized as well !!

vt circuit and optimizer is the problem, always is.

 

[REDSAW]

not totally clear, but looks like one constant temperature circuit (maybe to rads)
one is a variable temperature circuit, the othe looks like indirect cylinder feed.
forget cylinder for now
forget 40 rads for now
concentrate on the vt circuit, flow through pump and directly through 3 way valve into boiler return giving you boiler short cycling
manually open 3 port valve (this system will require removal of actuator head and screwdriver insertion ! this should send heat into vt circuit which could well be rad circuit (optimized if your unlucky)
once youve discovered which circuit the vt controls then you can balance the primaries (still forgetting 40 rads)
once primary is balanced then shut other 2 'zones' and balance your 40 rads as normal.give me a bell if you get stuck !

out of interest what controls the actuator ? gotta be a control panel of some sorts, open it up and have a look inside before belling me. dont need to tell you to be carefull in there !!

i actually did that shaun, opend up the pot valve, no scew driver just thumb n finger. all i got was luke warm (well, i could keep my hand there).
the switch panel is to the right of the exp vessell.
top of my head, 3 pump switches. temp copensator at 8 deg. holiday, timed, constant switch. control board temp?.

 

[migoplumber]

one main pipe out of the boiler is it hot metres away on flow/ return
relooking your pics. cylinder no pump, so 3 pumps are boiler shunt pump,vt,ct
shunt pump should be dead hot - same temperature as boiler flow. that leaves 2 pumps
i know they are red but could one be dhws return? only guessing. no matter what one of the pumos will be piping hot.
if the vt circuit is only hand hot that starts to sound like a valve problem, it too should be piping hot either recirculating or throwing water into heating circuit. if its not, pump problem, (air ?) or physical matter blocking 3 way valve, or just a plain old knackered motorized valve - they do get upset when they have a lack of water specially the satchwell jobbys !!

 

[REDSAW]

one main pipe out of the boiler is it hot metres away on flow/ return
relooking your pics. cylinder no pump, so 3 pumps are boiler shunt pump,vt,ct
shunt pump should be dead hot - same temperature as boiler flow. that leaves 2 pumps
i know they are red but could one be dhws return? only guessing. no matter what one of the pumos will be piping hot.
if the vt circuit is only hand hot that starts to sound like a valve problem, it too should be piping hot either recirculating or throwing water into heating circuit. if its not, pump problem, (air ?) or physical matter blocking 3 way valve, or just a plain old knackered motorized valve - they do get upset when they have a lack of water specially the satchwell jobbys !!

ahah, shunt pump that was it (middle one), whats a shunt mean?.
not in photo, behind cylinder is a bronze pump that is very hot and buzzin.
we cannot locate any hot pipes outside the room anywhere.so the only heat in piping is within.
flow n return for upstairs go up behind cylinder into a void. behind that wall is a susspended ceiling 2' lower than pipes and we cannot track them anywhere they just rise beyond the inner roof?.
shunt pump if i remember is not that hot.
the valves are a spanish or italian make dark grey?. i have a crap memory.lol.
my mate twazzled those tamp valves up to about 100deg, and back?.

 

[stevew451]

canyou back fill the system
remove any auto vents and try just with the valve beneath i know this one asnearly blew a boiler up with this one
the pressure unit is really just for topping up
is heating running to other circuits as mentioned above
check the system isnt on a timelock out that needs resetting

 

[WHPES]

On a system that size the installers should have left some documentation, wiring diagrams and possibly schematics with the customer. Have you checked for these?

 

[migoplumber]

shunt pump just recirculates the boiler flow and return pipes, sometimes through a header but not always.
bronze pump deffo dhws return, be aware that nowdays you will come across red headed grundfos on yellow bellies, (im talking grundfoss talk!!) all grundfoss pump impellers are now stainless steel. and its a lot cheaper to change head than new pump.
your shunt pump is hot indicating good boiler working temps.
problem is circulation. if the ct pump is hot with a good flow - turn it off. and concentrate on vt pump.
i know iits vague but really need to be there!!

 

[REDSAW]

ok lads, many thanks we got it sorted, well my mate did at 6am, i got up and just to knackrd and couldnt be rsed so i let him go on his own and met up with him at 10am (s.emp perk).
as steve said, we reconed it was timed out at 4pm just as most who knew were leaving for the day.
also as said, no schematics anywhere.

but as you suspected shaun, the 3 port behind boiler flue was stuck.sods law it was the only one that wasnt checked as it was obscured from view..
all happy now as monies on the way.
wey hey.

 

[Puddle]

Alls well that ends well

Whats that cofee taste like the next day

 

[REDSAW]

as bad as when it was PAID FOR!

 

[fuzzy]

why is there a filling loop to me that looks like a pump set to fill it from

its called a pressurisation unit. it auto tops up system. it usually does it 10 times and then locks out. if theres a drop in pressure you dont have to keep topping up with a manual filling loop. if it is a leak it will top up more than 10 times in a given period and go to lock out. therefore the engineer knows theres a problem

the system normally has a short constant temp circuit with other circuits off it, the 3 port works differently than on domestic by blending the hot water, saves the boiler from carrying on working when there is no need.
i worked on these years ago, used to love working them out! been a while though and would take some head scatching if i come acros them again!!!!!!!!!!!!!!!!!!11