Use of microswitch on Honeywell 2-port valve for auxilliary pump

[samwardill]

My boiler struggled to circulate throughout my house so my heating engineer installed an auxilliary pump a few years ago. On a recent service he identified that the auxilliary pump was not working. He said that it was down to the motorised valve and he wants to charge £350 to replace it. He said that there was no power via the microswitch on the valve when it was open. The valve was new in Jan 2018 (replaced by same heating engineer when the auxilliary pump was installed).

I have two questions:

• Is it intended that the microswitch be used to directly switch a load such as a pump? I see from spec on unvented components europe website that Auxiliary Switch Rating is 250VAC 4A so I assume this is OK (but wanted to check)
• Is replacing the valve really necessary or should it be first attempted to just replace the Powerhead? If it is just replacing the PowerHead then £350 sounds really excessive - right?

 

[ShaunCorbs]

No it’s not rated for a pump load should be used via a 6 amp relay

Yes does sound high

 

[samwardill]

No it’s not rated for a pump load should be used via a 6 amp relay

Yes does sound high

Thanks @ShaunCorbs . Any idea where I could source a suitable relay?

 

[samwardill]

Thanks @ShaunCorbs . Any idea where I could source a suitable relay?

How about this in this

 

[ShaunCorbs]

Something like this Din Rail Modular Contactor 25 Amp 2 Pole Normally open 240v Coil | eBay - https://www.ebay.co.uk/itm/173277861311?_trkparms=amclksrc%3DITM%26aid%3D777008%26algo%3DPERSONAL.TOPIC%26ao%3D1%26asc%3D20220706173935%26meid%3D7e7207b671ee4a03b9aabfef4421500e%26pid%3D101526%26rk%3D1%26rkt%3D1%26mehot%3Dpp%26itm%3D173277861311%26pmt%3D0%26noa%3D1%26pg%3D2380057%26algv%3DRecentlyViewedItemsV2Mobile&_trksid=p2380057.c101526.m146925&_trkparms=pageci%3Aea491de7-9035-11ed-9833-6ed2a2fe6737%7Cparentrq%3A973d9ccf1850ad33a7826b50fff9d57a%7Ciid%3A1

And an adaptable box