Boiler return temperature codes

[mec01]

I'm looking for the specific code reference that condensing boiler manufactures have to abide by to get certification. What code references the return water temperature through condensing boilers. I have some high efficiency condensing boilers that automatically cycle the bypass valves to self calibrate. The problem is that the boilers are rated for return water down to 50 deg F, but the valve cycling full open/close does not maintain the interal water temperature adequately to stop condensation in the primary heat exchanger. The net result is that the interal boiler controls are violating their own operational parameters by allowing the bypass valve which is designed to maintain temps above 130 deg F to allow lower temperatures to hit the primary heat exchanger. The condensate will destroy the primary heat exchangers

In summary............does anyone know the code reference so I can throw it back at the manufacture?

Thank you..........


p.s. No, we can't raise the outgoing temp,nor can we disable the automatic valve calibration.

 

[GenB]

You may be out of luck.
there is not Code mandating performance other than ASHRAE
your only choiceisto work with the mfr. by asking their advise.
you may want to add a metering oriffice in the return that way when the bypass opens it will be metered.
ER

 

[mec01]

I think you are correct. The manufacturer will have to get involved. They put floating poing valve actuators on the system that havet to recalibrate every 18 hours. Compounded by burning the calibration command into the main chip, there is only a couple of ways of bypassing the situation....both take manufacturer support. However, manufacturer support has been severely lacking during this project. The listing agencies have files on the boilers that they list. If all else fails, I can notify the listing agencies of issues and have them work with the boiler manufacter.

 

[GenB]

The listing agencies will not get involved in warranty complains.
you are asuming their help but as I said you may have to fix it yourself.
ER