Fernox F4 Central Heating Leak Sealer Express 400ml

By Fernox Product code: 83815 Pack size: Each

Selected
Quantity
Add to trolley for...

- Change your branch

Check stock in your local branch

Product Details

Seals small leaks and weeps which may cause pressure loss and boiler breakdown.

Technical Specification
Brand Fernox
Volume (L) 0.4
Delivery details

Covid-19 Update

  • Free Next Business Day delivery for orders over £25 to home and site is available for orders placed before 6pm
  • Saturday and Sunday delivery is now available for orders placed before 4pm on Friday for Saturday delivery and 4pm Saturday for Sunday delivery, see here for details
  • Pre-12 delivery service is now available. Place your order before 6pm Mon – Fri for next business day delivery by 12pm. Orders placed after 6pm Friday and before 6pm Sunday will be delivered by 12pm Monday. UK mainland
  • Once your order has been dispatched you will receive an invoice email with the courier details and your tracking number
  • Alternatively go to MyAccount, click on your Order History, click on the TRACK icon to link through to the carrier website and the tracking details for your delivery
  • Delivery direct from suppliers is now available and specific delivery times will be displayed on the product page
Order Value: Under £25 Over £25 but less than £75 £75 & Over
Next Business Day Delivery (Mon-Fri) usually before 6pm £5 Free Free
Pre-12 Delivery before 12 noon Next Business Day £10 £5 £5
Remote areas standard delivery (2-4 days) £5 Free Free
Saturday Delivery order by 4pm Friday £10 £5 Free
Sunday Delivery order by 4pm Saturday £10 £5 Free


Please note items delivered by our suppliers are not available for the options above. Delivery times may vary.

More about Delivery & Returns
Click & Collect details

Covid 19 Update

Click & Collect

  • Branches are now fully open and operating safely in line with government guidelines
  • Safe contactless collection is available 7 days a week at our branches
  • Our branches are open 7am-8pm Monday-Friday, 7am-7pm Saturday and 9-4pm Sunday
  • Keeping our colleagues and customers safe and well and respecting stringent social distancing requirements is our number one priority – 2 metre rule enforced
  • Our available product range will not require more than 1 person to lift
  • Please see our guide to click and collect below

  • Please ensure that your mobile number is added so that we can text you when your order is ready to collect

Call & Collect

Due to current trading conditions we have suspended our Call & Collect service until further notice.

If you are using our Click & Collect service please note the following:
  • Order online or over the phone and collect in branch from 5 minutes later.
  • Ensure you check stock is available for collection at your chosen branch.
  • Check branch opening hours to ensure you have sufficient time to collect.
  • For items not available for same day collection, place order before 7pm Mon-Fri (4pm Sun) and you can collect Next Business Day (Mon-Fri) after 3pm.
  • If we have your mobile number, we’ll send you a text when your order is ready to collect.
Reviews
Fernox F4 Central Heating Leak Sealer Express 400ml is rated 4.6 out of 5 by 21.
Rated 5 out of 5 by from Pressure loss sorted Heating system kept loosing pressure until this was used. Not lost pressure now for several months now
Date published: 2020-07-22
Rated 5 out of 5 by from Did the trick Fixed a drip from a radiator pipe
Date published: 2020-06-11
Rated 5 out of 5 by from Easy to use Solved a problem that I have had of loss of pressure for 2 months (LOCKDOWN!)
Date published: 2020-06-08
Rated 4 out of 5 by from Fingers Crossed! I bought two of these to use in a big CH system with a probable leak causing a very damp wall. Access was impossible without major works, so I thought I would try F4. The injections into a radiator was not as efficient as with other Fernox injectors, maybe because it's a thicker, foamier consistency. I probably wasted 10% but it seems to have done the trick and the wall is drying well.
Date published: 2020-05-30
Rated 5 out of 5 by from Great product Excellent product. Easy to use. Worked first time no problems.
Date published: 2020-05-28
Rated 5 out of 5 by from Worked a treat Apprehensive at first but thought its the same company that makes the filters for my boiler so gave it a go I was losing 1.7 bar to 0 bar in less than a day had two plumbers out neither could find any leaks so used this sealer nothing happened for 48 hours then no pressure loss boiler working as it should radiators working great so to the hot water its been a few weeks now since using and everything worki g fine and no pressure loss whatsoever I have since found where the leak was due to brown stain just needed a couple of compression joints tightening but would recommend fernox leak sealer all day long
Date published: 2020-05-27
Rated 5 out of 5 by from Does what it says on the tin Great product. My Baxi boiler had a solid filling loop rather than a flexi pipe so a little more fiddling than the Fernox Video to connect up but it did the job sealing a weeping leak from a weld on our bathroom towel rail. No draining or other messing about. Much cheaper at Toolstation than others.
Date published: 2020-05-20
Rated 5 out of 5 by from Pretty easy Very easy to use with a filling loop but would be useful to have a 1/2" female connector to put on the drain valve on magnetic filters
Date published: 2020-05-01
  • y_2020, m_10, d_29, h_16
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.12
  • cp_1, bvpage1
  • co_hasreviews, tv_0, tr_21
  • loc_en_GB, sid_83815, prod, sort_[SortEntry(order=SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_toolstation-gb
  • bvseo_sdk, p_sdk, 3.2.0
  • CLOUD, getContent, 25.02ms
  • REVIEWS, PRODUCT

You might also like

This site uses cookies to store information on your computer. Some of these cookies are essential to make the site work and others help us to improve services by giving us some insight into how the site is used. You can view our cookies policy here.

Hey, browse our site often?

ADD TO HOME SCREEN