End of my tether in understanding my CH/HW - Please help

[chipmunkcheeks8]

Hi All,
Ok just a homeowner and not an engineer/plumber and know very little about Central Heatings ( you might be able to tell by the way - I thought i understood the way my CH worked - Had different opinions from Engineers who i think simply don't have an idea either.Basically i have a new build 4 bedroom detached home over three floors ( 3 shower rooms and 15 radiators) which was bought off plan in 2007. I have a 24hxi Glow Worm Boiler in the integral garage which is never turned off ( which is next to the kitchen) with a control timer placed in the kitchen and a manual dial thermostat in the main hallway. I have a 250L Megaflow water cylinder in an airing cupboard in the bathroom with zoning valves and the water pump attached. I have a Danfoss digital thermostat placed in the smallest room on the first floor ( which controls the heating for the first floor and the 2nd floor bedroom). I tend to put my heating and water on a controlled timer rather than leave it on continuosly on a low temperature.The problem i have is that i have an odd pattern of hit or miss with the first floor radiators getting warm!!The digital thermostat on the first floor is all timed well and the reading is on at 21C however the radiators are cold ( however you may find that on another day the radiators are on as normal - no pattern). The thermostat seems to be in working order. I never had this problem in the first couple of years of using the CH when i bought the proprty. 4 years on and things seem to change - you know your heating system well especially when it is not functioning normally.I Had first noticed thsi problem over this summer when occcasionally we had the odd cold days i would switch the heating on and found the radiators would not warm up - was not sure if it was because the temperature upstairs was already at 21C ( the clicking noise of the Danfoss Thermostat was functional but if i increased it higher the radiators still would not get warm).
Ever since i noiced this problem i have been asking a few engineers but getting different theories.Had a number of theories;
1. Maybe i did not notice the previous winters as i left my heating on continuosly on a low temperature so radiators upstairs were always warm.( still debating whether this is the best cost effective energy efficient way of saving £) - going to leave my heating on a timer this winter for a change.
2. An Engineer said it could be the zoning valves being faulty or sticking? However the spring loaded effect seems to working ok ( have noticed sometimes the springloaded arms are not 'springing' back when using finger pressure and seem passive in movement - does not happen all the time and no difference whether the heating is on or not - are these springloaded arms suppose to be active when the water/heating is on or off?)
3. Another Engineer said that if the hot water is heating up at the same time as the radiators/CH switching on then the priority goes to the water cylinder tank, which delays the heating of the radiators upstairs - i.e once the cylinder hot water has reached its temperature then the radiators upstairs will start to warm up. I never noticed this pattern before but saying that i use to leave my CH/HW on continuosly over winter on a low temp and control this with the thermostats. Does this mean i should put my CH/HW at different times of the day, howevever this is not always practical when you want to wakeup with hot water and warm house in the short time you have before going to work ( and vice versa when you come home from work).

I simply do not know where to start with resolving this problem and have lost the heart to believe any engineer. Any suggestions where to start?Thanks People

 

[WHPES]

question 1 - do you have any radiators with thermostatic valves fitted in the same rooms as the wall thermostats?

 

[tamz]

Having read through your post i am still none the wiser as to your problem other than the 1st floor doesn't heat up.

Spliting your post into paragraphs would help but also you need to explain exactly what your system is. How many zones are there. what type of valves. Is the cylinder on the first floor etc etc.

Post a photo would answer some questions.

 

[SimonJohns]

I'm betting on balancing

 

[WHPES]

Yes, that was my second thought.

Problem is I find that a lot of younger plumbers are hopeless with balancing systems. Maybe I'm being a bit unfair, but the guys I have seen seem too impatient to do the job properly, or maybe don't have enough knowledge.

 

[tamz]

Bit of both probably.

 

[SimonJohns]

Yes, that was my second thought.

Problem is I find that a lot of younger plumbers are hopeless with balancing systems. Maybe I'm being a bit unfair, but the guys I have seen seem too impatient to do the job properly, or maybe don't have enough knowledge.

My dad taught me. And he didn't understand Balancing. Lucky I'm a good self learner and paid attention on my day release

 

[REDSAW]

heat rises is my tip!.

 

[chipmunkcheeks8]

Hello people,
Many thanks for taking the time to reply - only just joined and did not think i would get any responses so quickly. The cogs in my head are turning. Answer to questions;
1. Just to clarify what system i have - Condensing Glow Worm 24HXI boiler with a 250L Heatrae Sadia Megaflow Water Cylinder which is on the first floor.

2. The rooms which have thermostats controls on the wall ( Downstairs hallway and First floor small bedroom) - their associated radiators do not have TVR's thermostats attached ( TVR's - is that right ? or is it TRV's)

3. Balancing - recently balanced ( or what i thought would be balancing) as i had a power flush done of the Central Heating ( Took 6 hours to do) for a seperate problem - long story but my water pump failed for the 2nd time so it was assumed that when the CH was initally installed by the subcontractors for the builders, they probably didnt do a powerflush - or possibly half a job. How do you balance radiators? Or the question i should ask how can i tell if a radiator is balanced or not? From what i know i need to look a the other end of the radiator ( the end without the thermostat) and see how far this 'nozzle' has been opened - is that right?

4. Photo of the Water cylinder attached - where it is labelled on the zoneing valves;
Z1- Controls the first floor ( not sure if the 2nd floor top room)
ZG-Controls the Ground Floor
Not sure what the other Zone valve is for

An Engineer told me if the main controls for the CH/HW which is in the kitchen) are timed to be OFF, then i cannot override this with the upstairs thermostat  - however i tried this the other day and i can - i manually increased the temperature on the digital Danfoss thermostat and the typical 'click' occured indicating that it was active and then the usual 'gurgling' from the water cylinder occured and i could feel after 10mins the upstairs radiators coming on ( checked downstairs in the kitchen and the CH/HW was programmed to be off) - this is what i mean when i hear different opinions from different engineers.  HOWEVER this does not always happen - one time i tried this and the Upstairs thermostat did not click and was passive and nothing happened with the radiators! - one theory is that maybe the radiators will come on when there is enough hot water in the cylinder to distribute it to these.

I think i am going round in circles!! Aha
Sorry for any confusion

 

[chipmunkcheeks8]

Any feedback on my last post guys? Or is it too complicated to figure out - i think i may have lost you all. Aha

 

[tamz]

Just reading through your last post (#9) i would suggest getting the system wiring checked before doing anything else.
It might be a better option to fit programmable thermostats than basic ones where you set times and temperatures directly from there and use the main programmer in the kitchen solely for HW.

The other zone valve is for the hot water btw.

 

[doitmyself]

First thing to do is check that the two heating circuits can act independently. You don't say if you have separate timers for the heating circuits. If you do, turn the ground floor timer off and the bedroom one on. (If no separate timer, just set the downstairs stat to minimum) Set all bedroom TRVs (TRV is a make of car!) to max and turn the bedroom stat to max.

See if the bedroom rads get hot. If they do, the circuits are completely separate. The problem is balancing

If they don't get hot, turn the downstairs Timer ON but leave the downstairs stat on min. If the bedroom rads get hot, you know they have common timings but can be independently temperature controlled. That's OK and the problem is balancing

If the upstairs rads still do not get hot, turn the downstairs stat up to max. If that works you know that the upstairs rads will only heat up if the downstairs is also calling for heat. That's not correct. Even if the same times are used, you should still be able to control temperatures independently. The wiring is incorrect.

 

[Niekolye]

^ genius.

 

[AmritPedersen]

It does seem rather complex.

Ok, easy bit first: The unmarked 2-port valve is probably for the unvented cylinder.

Generally, the controller in the kitchen should run the room stats as well as the hot water cylinder. Is it a 3-channel controller? ie can you programme the 2 heating zones & the hot water individually from this controller? If its a 2-channel one, then the wiring might be more than a little inventive, or the top room stat is either programmable or is directly running the 2-port valve without a timer.

Tho, its often the simplest reason. The people who did the power flush, did they carry out any alterations or adjustment? It might be good to get back to them & clarify the problem.