Need wiring diagram help...(JohnNY)

DaveC

The system is piped as shown (yes, much hardware omitted) and should be able to stay that way. Where I'm having trouble is staging the burners while energizing a single pump...twice.

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DaveC

I've created a monster that I can't control.

I'm using a Tekmar 264 (4-stage, DHW) control. I would just love to stage the burners for heat and DHW, but would settle for four stage heating I'll work out the domestic.

I could really use some help here and thank you in advance.

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Constantin

Does this help?

A double-reverse-return to keep the water temperatures constant. With FC-circs, you should be able to limit the amount of ghost flow? Valves have been omitted due to laziness & clarity.

Also check to see to what extent you can set the priority on the Tekmar. On my boiler, I can dial in just how much priority it'll give to the indirect over the heating system. That may be all you need to keep the Ergomax happy.

Lastly, you could consider a 4-way valve, variable-speed injection, or somesuch to allow the boilers to maintain a happy temperature for the Ergomax, yet provide a different (and presumably lower) temperature for the heating system main supply line.

Al Letellier_9

tekmar staging

Contact your local Tekmar rep..that's what he's there for. I believe you can program the 264 to run one or both boilers for domestic call on priority setting. Unless you have an unusual domestic load, one 334 and that tank should make a lot of hot water. We just completed a similar setup and we only run one boiler for domestic in WWSD mode.

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Rodney Summers

i agree.....

what's the logic for connecting 2 feeds (& thus 2 returns) to the indirect. why not just feed the indirect off the "1st" 334 (always) and let the 2nd 334 only come on for close to design heating loads. the only reason i can think of to pipe it your way would be if there is a consistently large dhw load (is that true?) or if the tekmar forces boiler rotation automatically (but that's probably an option that can disabled) or if you just want to use rotation. if rotation is a must, then you add some relay logic and flow control such that the secondary boiler legs to the indirect are off when the 'other boiler' is the primary. you can choose to have the logic on all the time or to disable when both boilers are active (in which case they would both feed the indirect).

ss

clammy

piping

I wa s just wondering if if had piped the boiler was the diagram shows ?I would jusy wonder about each boiler while running under design load would see different return temps piped the way the diagram ia showing .Should there only be one set on tees installed in the primary and from there the boiler piped reverse return so that both boilers would see the same return temps .I did bid a job using the same concept of staging the burners and was looking at the buderus logimactic (older ) and a tekmar staging .I do belive i would just put the indirect right on my secondary loop instead of the way your diagrams shows it,it would probalbly be easier to rotate the boilers for domestics production and alo set it up on a timer also .Peace and good luck

clammy

piping

I wa s just wondering if if had piped the boiler was the diagram shows ?I would jusy wonder about each boiler while running under design load would see different return temps piped the way the diagram ia showing .Should there only be one set on tees installed in the primary and from there the boiler piped reverse return so that both boilers would see the same return temps .I did bid a job using the same concept of staging the burners and was looking at the buderus logimactic (older ) and a tekmar staging .I do belive i would just put the indirect right on my secondary loop instead of the way your diagrams shows it,it would probalbly be easier to rotate the boilers for domestics production and alo set it up on a timer also .Peace and good luck

Constantin

Very good point also...

... that is why I called for reverse-return as well. I figure that with priority and a relay (if needed), the two circs on the boilers can satisfy the IDWH quickly, then go back to providing staged output to the pri-sec line. That should also help the Tekmar sensors, as one sensor can monitor the staged output of both boilers before their heated water reaches the pri-sec line.