Tekmar 361 (or as we call in Kanmor 361e)

SavUK

When I moved into my new home which is here in the UK, I inherited a variable speed injection system that I believe is the same as the Tekmar 361 as you, across the pond" would call it. It has never worked properly since I moved in.

I have copied pictures of the system and have full diagrammatics. The main problem is, that I can never get the water up to temperature. I think that one of the issues is that the system isn't pumping enough hot water into the loops to counteract the loss of radiant heat through the floor and so the return temperature stays static. (Also I'm on metric so I'll have to do some translations!)

What's the best way to get the thing up to temp from a relatively cold start? If anyone can help it would be greatly appreciated, as it seems no one on this side of the pond has this sort of system and they all seem to use mixing valves.

(I also know that my injection pump is the wrong type, but that's secondary at the moment as I'm never in a position for the pump to ramp down).

hot_rod

I don’t think you can modulate an ECM type circ with that control. Maybe just switch the pumps and give it a try? Although that 25-80 is probably too large for your injection circ. It may still ramp up and down enough.

SavUK

No, I know, but at the moment the controller is calling for 100% all the time so ramping down isn't an issue🤣. 

hot_rod

Assuming both circulators are spinning, flowing the proper direction?
Any design spec, temperatures or flow rates?
Any strainers in either loop that could be plugged? valves partially off?
Has it ever worked properly?

The upper loop, of course needs to be hot enough and have adequate flow rate.

Here is the mixed temperature formula for showing what is expected with knowing a couple inputs. Can you measure temperature in the upper loop? Know or measure flow?

In this example 170F at 2 gpm is injected into the secondary loop. Does that Alpha indicate flow on the display?

The 25-80 as you can see is a much bigger, probably high head circ. That is as older non ECM version, a Euro pump judging by voltage The date code is in the serial number year and week typically.

What type of tube or loop lengths? Just 4 loops on one manifold? Seems like a lot of pump. Are there flowmeters on the manifold? Are they moving, reading a flow rate? Around here .5 gpm 2 lt/min. per loop, so assume 2 gpm 8 lt/m
Look up the pump curve to get an idea of what it can pump.

Might try closing down the red handle valve a bit, see if temperature changes to manifold.

STEVEusaPA

Maybe it’s just not programmed correctly

SavUK

As you can see, it's a pretty big system!
I have an 11 port manifold downstairs and a 6 port manifold upstairs.

Flow rates and system specs are on image.

So at the moment I have tested closing off all the actuators so that I have the minimum volume of liquid going through the system and I see an increase in the temperature of the water in the loop, so I'm assuming that the circulator is working fine. I can also adjust the flow valves and these will move up and down showing water flowing through the system.

The upper loop is usually around 60 Celsius (140 farenheit).

Alpha doesn't show flow rate, but at the moment it's running on highest setting, and I think it can pull through about over 3m cubed an hour (so I'm guessing about 15g/min. I'm guessing that the system isn't pumping that through though.

I'm not even sure that I've balanced the return valve correctly. Essentially I put my hand on it, and close the return until hot water starts to flow down through the pump.

I know that I have to replace the pump with a non ECM, but I'm not even sure what model a capacitor-driven wet pump is.

I think what has been happening is that the thermal energy being radiated from the floor has been equal to the heat put into the system meaning that the system has sort of reached an equilibrium and temperature remains low.

I'm looking to replace the Alpha with an old Grundfos UPS 15-50, but they don't make them anymore!
https://product-selection.grundfos.com/uk/products/up-ups-series-100/up-ups/ups-15-50-130-59525600?tab=variant-curves&pumpsystemid=1715038981

Hope that all makes sense

SavUK

They are my instructions.

SavUK

Sorry it's all in metric!!!

SavUK

To be honest I think that possibly the boiler isn't working correctly either, but not sure. The system seems to fire up, heat the water to 70 then ramps down.

The temperature drops to 60 ish and the it cycles again.

I've attached a full picture of the setup

hot_rod

Might try running the boiler temperature up. Injection mixing systems need some differential to move heat.
If it drops to 60c you don’t have a lot of temperature difference to work with
Is the ground floor a concrete slab?

With a load on the system I would expect the boiler to run long cycles, on a very cold day, possibly non stop

If it is cycling often, sounds like it is not able to move the heat into the system

If the injection pump is running 100% it should not be a setting issue.

hot_rod

Looks like a condensing boiler? I wonder why the injection mixing arrangement? Over here we would run the boiler at 82c to run injection mixing

STEVEusaPA

Considering you have all that paperwork and documentation, can you contact/track down the original installer or designer? Seems like someone put a lot of thought into the design of your system.

SavUK

Thanks for the help.

The original company no longer exists, as that was my first port of call.

I turned the boiler down to 60 (140), in the summer as it was just needed for Hot Water. I didn't think about putting it back up as someone said the lower you can run it the cheaper it is!

I'll try turning the boiler up when I get back home. The pump has too many different settings, and it's trying to decide which one to use to get the most water into the system. Does the setup for the return valve sound right?

SavUK

Well I've cracked the boiler up to 80c. Fingers crossed

hot_rod

Do you have a sheet in the design that shows total flow required and required temperature? With that you can calculate where the boiler temperature needs to be set. Using the formula I sent above.
The tekmar/ Kanmor installation should have that calculation info also. Probably in metric units

SavUK

Not that I can see. I think I have sussed the problem though. I think that the motorised valve on the boiler loop has failed. I think that when hot water is called for this isn't opening correctly. Well, that's my theory for today anyway!

SavUK

So after a bit of playing around with the system, I changed the thermostat on the hot water tank rather than on the boiler. The motorised valves were all working, but when the tekmar (kanmor) is asking for heat it can't independently fire up the boiler.

So if I drop the thermostat on the tank, the valve closes, but the boiler doesn't fire up!

hot_rod

Too many little pieces of your puzzle, dribbling in
Is the buffer tank and indirect water heater? or is there a buffer for the heating.
Sounds like a electric zone valve chooses heat or hot water? Hot water call allows boiler to ramp up to 80C?

The boiler was calling fine yesterday and all you did was turn up the boiler temperature?

It really depends on how the control logic was designed. The outdoor reset function. is on both your boiler and Kanmor. They need to communicate properly for all this to work.

Typically a call for heat from a room thermostat. Actuator on the manifold signals the Kanmor to call the boiler and regulate the injection is my guess.

Was a wiring schematic included with the design package? if not you may need to reverse engineer the system control logic.

It looks like a nice assembly of components, what it needs is a knowledgable commissioning agent. is 007 available?

SavUK

That was the problem, too many variables!

Anyway problem has been solved. The Honeywell Motorised Valve was busted, and so its microswitch wasn't sending a signal to the boiler for hot water.

The boiler was calling fine yesterday as the thermostat on the hot water tank was set too high and was constantly demanding water. This disguised the fact that the control centre wasn't asking for hot water, it was just using some of the supply asked for by the hot tank.

I turned the thermostat down on the tank until it stopped calling for heat, this should have closed the motorised valve and allowed the hot water just to go to the UFH.

Motorised valve closed as expected, but when call made to boiler there was no response. So indeed it was a busted motorised valve hidden by a thermostat set too high!

Thanks for all the input...... Now to look for that pump.