Replacing old relay with the new Honeywell R8845U1003 wiring questions

Reply

  #1  
Old 11-10-12, 11:35 AM
Member
Thread Starter
Join Date: Nov 2007
Location: Usa
Posts: 138
Received 0 Votes on 0 Posts
Replacing old relay with the new Honeywell R8845U1003 wiring questions

Hello,

I want to replace my old relay with this new one i bought from Pexsupply, R8845U1003.

I have some questions after looking at the schematic.

THe new relay has the following connection points,

1) R(T) / W(T) / C -> I know this goes to the themostat, its already on my old relay
2) X1 / X2 --> I know this goes to the side of the boiler , its already on my old relay
3) L1 / L2 --> I do not know where this is suppose to connect to?
4) N.O. / COM --> I do not know where this is suppose to connect?
5) A / B --> I dont think i will use these.

On my old relay, there are 3 sets of Red/White wires.

Set1) Red/White coming out from the boiler switch
Set2) Red/White wire coming from Circulator
Set3) RedWhite/Black wire coming out from the relay itself. (I did not open the relay, but its coming out from the center of the relay covering with a metal plate.

I think L1 and L2 is to connect it to Set1.
I think N.O./COM is for Circulator.
I think A/B is not used.

Can you help me confirm?

Also for the poplarity - if above assumption is correct,
--> is L1 (HOT) for RED, L2 (LOAD) for WHITE coming out from Set1 above?
--> Is COM for RED, and N.O. for WHITE coming out from Set 2?
--> How to connect Set3? (White/Red/Black coming out from relay)

Thanks. I attached a better picture of the existing wiring on existing relay.

Thanks,
 
Attached Images  
Sponsored Links
  #2  
Old 11-10-12, 04:16 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
What's the make and model of the existing relay?

And also again please, the make/model of the boiler?
 
  #3  
Old 11-10-12, 06:29 PM
Member
Thread Starter
Join Date: Nov 2007
Location: Usa
Posts: 138
Received 0 Votes on 0 Posts
I could not information of existing relay.

The boiler is hydrotherm hc-145

Thanks.
 
  #4  
Old 11-11-12, 04:21 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I've been thinking about this while outside today cleaning up leaves...

You need to know exactly where each and every wire comes from and their function before you start replacing that relay. If you don't, you can fry something right quick, maybe even yourself.

Is there a schematic diagram for your boiler pasted onto the inside of the front cover? If so, can you photograph it clearly enough and high enough resolution that I can see what that relay is doing?

I found manual for NEWER HC boiler on line, but I don't think it's using the same relay... and not much help deciphering what you've got there.

In your photo, you say " To Boiler X1 / X2 " but that is near the transformer in the old relay. The white and black wires should not be going to X1 / X2 on the boiler, they are 120VAC power for the transformer. Be careful! Don't blow up your boiler by feeding 120 VAC into the X1 and X2.

THe new relay has the following connection points,

1) R(T) / W(T) / C -> I know this goes to the themostat, its already on my old relay

Yes, sounds right.

2) X1 / X2 --> I know this goes to the side of the boiler , its already on my old relay

Yes, sounds right. But pay attention to what I said about this, above.

3) L1 / L2 --> I do not know where this is suppose to connect to?

These are the 120VAC power going into the new relay, and most likely the red/white pair from the boiler switch as you have said below.

4) N.O. / COM --> I do not know where this is suppose to connect?

I believe you are correct that these would switch the circulator

5) A / B --> I dont think i will use these.

Probably correct

On my old relay, there are 3 sets of Red/White wires.

Set1) Red/White coming out from the boiler switch
Set2) Red/White wire coming from Circulator
Set3) RedWhite/Black wire coming out from the relay itself. (I did not open the relay, but its coming out from the center of the relay covering with a metal plate.

I think L1 and L2 is to connect it to Set1.

Probably correct

I think N.O./COM is for Circulator.

Probably correct

I think A/B is not used.

Probably correct

Can you help me confirm?

Also for the poplarity - if above assumption is correct,

--> is L1 (HOT) for RED, L2 (LOAD) for WHITE coming out from Set1 above?

L1 is always 120VAC HOT and could be RED or BLACK

L2 is always 120VAC NEUTRAL and is always WHITE


--> Is COM for RED, and N.O. for WHITE coming out from Set 2?

NO! absolutely NOT! All WHITE are NEUTRAL! If you connect like that, nothing will happen... the circulator simply will not run... hopefully... or, you could possibly short out the 120VAC and make lots of sparks and destroy the relay if you fudge it up.

ALL WHITES remain connected together.

The RED wire from the circulator will go to the NO terminal. You will have to add a jumper wire from L1 of the relay to the COM terminal in order to power the relay when those contacts close. See the examples in the 8845 installation manual.

I have to warn you at this point that if you are this unfamiliar with 120VAC circuits, you should not be attempting this.


--> How to connect Set3? (White/Red/Black coming out from relay)

This depends on the function of 'set3'. DO NOT GUESS! YOU MUST KNOW WHAT THEY ARE FOR BEFORE CONNECTING THEM TO ANYTHING!
 
  #5  
Old 11-11-12, 09:48 PM
Member
Thread Starter
Join Date: Nov 2007
Location: Usa
Posts: 138
Received 0 Votes on 0 Posts
Hi,

This gentlmen asked similar question as me before, but he knows alot more than me. (And you also helped to answer his questions).

he has HC boiler just like me, and the picture of his relay, looks like mine. (i would say exactly), and he has a schematic of his relay posted.

the post:
http://www.doityourself.com/forum/bo...j-trooper.html

His picture links:
boiler-relay Photos by rviger | Photobucket

His relay:
IMG_3534.jpg photo by rviger | Photobucket
IMG_3538.jpg photo by rviger | Photobucket

His schematic of relay:
IMG_3548.jpg photo by rviger | Photobucket

his relay 's wiring is very very very very similar to me. It has 3 wires coming out from the relay itself.

My boiler/relay does not have schematics. Can you help me determine how to connect "set 3"? and confirm if the previous questions/answers is still correct?

Thanks.
 
  #6  
Old 11-12-12, 04:13 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
OK... I understand now. You should have showed me a pic of the top of the relay and then I would have recognized it.

You don't need to do anything with 'set3' because those are going away when the old relay does.

After the old relay is removed, you will have:

RED (120VAC HOT) from the boiler switch
WHITE (120VAC NEUTRAL) from the boiler switch

You called these set1

RED (120VAC HOT) supply to the circulator
WHITE (120VAC NEUTRAL) to the circulator

You called these set2

Wires from thermostat. You know where they go.

Wires from X1 / X2 . You know where they go.

Here's what you need to do:

RED from boiler switch to L1 on the 8845

You need to install a JUMPER (RED OR BLACK) from L1 on the 8845 to COM on the 8845

RED from circulator connects to N.O. on the 8845

WHITE from boiler switch to L2 on the 8845 AND to the WHITE from the circulator.

It is NOT a good idea to connect two wires to either L1 or L2. The chance of them loosening up is large.

What you want to do is put a SINGLE SHORT WIRE ( called a 'pigtail' ) on each of the L1 and L2 connections and use WIRE NUTS to connect the other wires, just like what is in the old relay for the WHITE wires.

So, put a short WHITE on L2, and connect the WHITE from the boiler switch and the WHITE from the circulator to it with a wire nut.

Put a short RED or BLACK wire on L1 and connect the RED from the boiler switch and the JUMPER to the COM with another wire nut.

If any of this is unclear or confusing, PLEASE ASK BEFORE YOU BLOW SOMETHING OR YOURSELF UP!
 
  #7  
Old 11-12-12, 08:57 PM
Member
Thread Starter
Join Date: Nov 2007
Location: Usa
Posts: 138
Received 0 Votes on 0 Posts
Thank you. I understand now. I will take a look first.

Thanks.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: