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Horstmann 425 Tiara Programmer

Product Code: 18470

Rated 4.2 out of 5 by 18 reviewers.

Common timing. 3-wire installation. Override facility. BS EN 60730-2-7: 1992 and 8182 / 8319, BS EN 50081-1 and BS EN 50082-1: 1992.

  • 24 Hour Programmable
  • 26 Pre-Set Programmes
  • 2 On/Off Periods per Day
  • Suitable for Gravity-Fed & Pumped Systems
  • 2 Year Manufacturer's Guarantee
  • 3-Wire Installation
  • Energy Saving Trust Approved
  • View more information

Switching/contact rating: 6A. H x W x D: 112 x 153 x 33mm. Backplate fit: 9-way (included). Not suitable for underfloor heating.

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Horstmann 425 Tiara Programmer Instruction Manual

£31.99 (inc. 20% VAT)

4.2222 5 18

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Rated 5 out of 5 by Compatable replacement. I'm an electrical contractor. I was called to a house that had a Horstmann Diamond programmer built in the 60's which was now sometimes sticking. I Spoke to Horstmann technical who suggested Horstmann 425 Tiara Programmer. What an excellent choice, a breeze to install and all working o.k.. If this one lasts as long as the old Horstmann Diamond, the customer will be well happy. This item was cheaper from Screwfix than any of my electrical wholesalers. Well done Screwfix. 23 Jul 2014
Rated 2 out of 5 by Horstmann Tiara 425 I was initially quite impressed by this programmer: it seemed to work satisfactorily, and appeared to be good value for money. However, after approx 18 months of operation, I experienced erratic operation of my heating system: domestic hot water (DHW) worked OK, but central heating often failed to start. (My heating system uses a motorised 3 port valve, and both DHW and CH are pumped.) After much investigation, I found that the fault was caused by intermittent closure of the DHW switch, when in the "off" position. I have dismantled the mechanism, and the fault is caused by poorly toleranced plastic in the switch leverage system. I would NOT recommend this product. 5 Nov 2013
Rated 5 out of 5 by Simples Good basic Programmer Doddle to fit Does what it says on the tin 5 Oct 2013
Rated 5 out of 5 by Best make of heating control This heating control box was easy to fit and easy to set for programming etc. The price was competitive and prompt delivery. 25 Dec 2012
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Brand Horstmann
Model No 425 Tiara
Pack Size 1
Product Depth 33 mm
Product Height 112 mm
Product Width 153 mm
Total Product Weight 0.43 kg