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jj, HVAC Mechanic
Category: HVAC
Satisfied Customers: 163
Experience:  your air.
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We have a Honeywell ST6400C heating programmer which needs

to be reset as it... Show More
to be reset as it has cut out as it thinks the boiler needs servicing. The boiler has been serviced but the engineer did not reset it, help please.

Kind regards,

Submitted: 4 years ago.
Category: HVAC
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BillyHvac, Journeyman HVAC Tech
Satisfied Customers: 22347
Experience: Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
replied 4 years ago.

sorry for the delay. Do you still need assistance?


Customer reply replied 4 years ago.

YES, still waiting.



BillyHvac, Journeyman HVAC Tech replied 4 years ago.

Thank you,

Is the unit currently off and not running due to the timer expiring?


Customer reply replied 4 years ago.

Unit is working but only allowing us to have it on for an hour at a time by pressing the "extra hour " button. Ititially it switched the boiler off. When the hour is up it will switch the boiler off again and we will have to press "extra hour again to get it to switch the boiler on again.



BillyHvac, Journeyman HVAC Tech replied 4 years ago.

The 6400 series was upgraded to the 9400.

I am attaching a manual. On page 5 it will begin to discuss the menu set ups.

Then on page 6 it specifically starts on how to change the service timer.

Try this first then let me know result and we can move forward. It will save much typing on both of our parts to move forward with the manual instructions.



Customer reply replied 4 years ago.

We have already looked at this and the 9400 needs a PIN code to reset it and ours does not have a facility to do this ! We have already dowloaded and printed out that manual and it does not help ! There must be a way to reset the ST6400C and this is what we want to know !



Customer reply replied 4 years ago.
Relist: Other.
Satisfactory answer not received yet !
jj, HVAC Mechanic
Satisfied Customers: 163
Experience: your air.
replied 4 years ago.
I am here to help. Please patiently disregard what you think is wrong because I am depending on you to be my eyes and hands to work that out.
I would like to help. I submitted an enquiry on your behalf to I will reply when they answer me. It may be beneficial for you to follow the same procedure. They may have someone on staff who is immediately available.
I will be able to call them here on monday morning if I haven't received a reply by then. I tried just now with an answering machine response.
In the meantime you may try to remove the batteries and the hard line power for at least two hours. It has a capacitor backup that will take at least two hrs to die ven with both the batteries and the hard wire removed. Make sure you can re program it because it will lose everything. it may be wiser to wait til monday if system is providing heat.
The site will keep this open til Monday when I get an answer.
jj, HVAC Mechanic replied 4 years ago.
I have received a reply from Honeywell. They said that there is no pin on the ST6400C heating programmer. I have replied back is there a reset?
I will relay there reply.
jj, HVAC Mechanic replied 4 years ago.

Attachment: 2013-02-04_173603_st6400s-product-specification.pdf Does this help? I am awaiting the reply but from the literature that I read it is not user configurable.

jj, HVAC Mechanic replied 4 years ago.

Attachment: 2013-02-05_124846_en0r8542_r1_2005_service_timer_access_instructions.pdf

Ok HoneywellUK has replied. The instructions are on page 2 of this document.