240v Relay 2x N/O contacts

[londonlec]

Hi Guys/Girls,


I will soon be wiring 2x Amptec boilers, and the instructions are asking for a relay to switch one pump (100w tops).

The instructions say:

240v Relay, 10amps, 2x normally open contacts, coil to contact isolated to 400v.



This relay from Heatrae is £140, can someone point out a suitable cheaper alternative from RS or Maplins please?
I have had a look but am struggling to find one with the 2x contacts required.

Hopefully I can find a suitable din rail mounted jobby.


Many thanks for your help!

 

[londonlec]

Am I right in thinking I can use a standard relay, with aux contacts clicked into the side?

 

[Knobhead]

A bog standard 230V 8 pin relay and base. £10 tops! RS Maplins Etc....

 

[Deleted member 9648]

one of these......Buy General Purpose Relay 8 pin DPCO plug-in relay,10A 230Vac coil RS BTA1-2C-230VAC online from RS for next day delivery.

 

[Dunc]

Just go to your local Neweys and ask for a 10A 8 pole relay with a 230V coil. You'll need an enclosure to but it in most likely but that will only put you back another fiver.

 

[londonlec]

Nice one guys for the fast replies.

My next mission... wiring the base lol!


Am I on the right lines?

Terminals 2 - 7 = Pump L and N
Terminals 1 - 3 = Switch line One L + N
Terminals 8 -6 = Switch line Two L + N


Edit:
I seem to be getting in a muddle with this, the diagram I'm looking at looks to show one coil whitch operates two switches.
I need 2x contacts to pull the relay in, one or other of the boilers.

 

[Dunc]

Don't surpose you can link us to the wiring diagram you are looking at?

 

[Knobhead]

You’re confused?
Please describe exactly what you want the system to do, don’t worry about the contacts yet we’ll get to that once we have the information.

 

[Knobhead]

Re-reading your OP you need X2 8pin relays to control the pump.

 

[londonlec]

Sorry guys I really appreciate the help.

Ive just noticed two sites with conflicting information, at time of posting I was looking at:

How To Wire A Relay


Two boilers will run together, via external controls.

Each boiler has a pump output, the pump will continue to run for 5 mins after the heating demand has stopped, to dissipate the heat.

Now if I simply connect both these terminals together, then into the pump, it will backfeed the boiler, making it run continuously.

I need some kind of a relay so that when boiler one says on, the pump comes on regardless of boiler 2.
So when boiler two says on, the pump comes on regardless of boiler 1. Ie the pump isn't physically connected to either boiler, but instead connected through a relay.


How about:
http://uk.rs-online.com/web/p/general-purpose-relay/6220547/

 

[Knobhead]

Read #9

 

[Dunc]

Yep, you need two relays as Tony says. Send a two core from each pump output on the boilers to the coil of each relay. A permanent live and neutral then goes to the common terminals of the relay then the pump connects to the NO contacts. I can't remember how you wire these boilers exactly but i'm assuming you have a separate control circuit for this system fed via a FCU along with the 2 high load feeds for the heating elements. The common terminals on the relays should be fed straight from the FCU and the enclosure labelled to indicate that multiple supplies are present at the enclosure.

 

[londonlec]

I think Ive got it! Many thanks dunc and tony, I'll have a sketch tomorrow when my brain is fresh! You've saved my client £140

 

[Dunc]

I think Ive got it! Many thanks dunc and tony, I'll have a sketch tomorrow when my brain is fresh! You've saved my client £140

Or made you £100 profit!

 

[Knobhead]

My fee is £50 :shuriken: