Make-Up Air Heaters When Warehouse Doors Stay Open in Winter — Preston

Make-up air heaters in Preston exist for a winter problem other heaters cannot solve: the doors stay open. Cross-docking, marshalling, waste bays and some production lines will not run with the shutter down. Extract fans still pull. Cold Lancashire air still has to come from somewhere.

This is not a warm-air servicing clone, and it is not a door-heater post. Make-up air (MUA) is dedicated plant that replaces extracted or lost air with tempered air so the warehouse does not suck a gale under every door.

Open doors plus extract equals a winter vacuum

On Walton Summit, Bamber Bridge and Leyland sites we see the same physics every freeze:

• Extract in packing, welding or process runs all shift
• Dock doors cycle or stand open
• The building goes negative
• External doors whistle; personnel doors slam
• Warm air heaters and tubes work harder and still lose the floor

A door heater can take the edge off a person in the opening. It cannot replace thousands of cubic metres of air an hour. That is the MUA job.

If you do not have make-up air and doors must stay open, winter comfort will always be a fight. If you do have MUA and it is in lockout, dirty or interlocked wrong, you already paid for a solution you are not using.

What fails on make-up air heaters in a freeze

• Burner lockout after a windy night
• Filters blocked with autumn dust, then icing on the intake
• Recirculation or fresh-air dampers stuck on a summer setting
• Interlocks with extract or doors that no longer match site operation
• Discharge aimed so it never reaches the occupied zone
• Gas pressure and modulation unable to hold leaving-air temperature at -3°C

A make-up air heater that “ran last winter” still needs a service. Intake conditions in a Lancashire freeze are the hardest of the year.

Winter checklist for Preston MUA plant

1. Confirm you actually have MUA, not just a large warehouse heater near a door.
2. Service before the freeze — burners, fans, filters, dampers, flue, gas train and controls.
3. Match the heater to extract. Added extract capacity creates a new winter draught.
4. Check door and extract interlocks. MUA should run when the building is pulling air.

• Walk the intake. Snow, polythene, collapsed bird screen or a damper frozen shut can starve the burner.
• Do not turn MUA off to save gas while extract still runs. You will pay in door heaters and staff complaints.

AAC Gas (Gas Safe 562186, Higher Walton) service commercial make-up air heaters as well as the door and warehouse heaters they support. Large industrial process air plant may sit with sister company SMR Gas Maintenance.

MUA vs door heaters vs warehouse heating — keep the roles straight

• Make-up air replaces air the building is losing
• Door / bay heaters protect people and the threshold
• Radiant tubes / warm air heat the occupied warehouse

Winter call-outs go wrong when a site asks one of those to do all three.

FAQ: make-up air heaters in Preston winters

Do we need make-up air if we already have warm air heaters?

If extract or open doors move more air than the building can replace quietly, yes — or you will keep turning warehouse heaters up and still feel a draught at floor level.

Can make-up air run with warehouse heating off?

Sometimes, if the only winter load is the open dock. An engineer should set the sequence so systems are not fighting.

Why does the MUA trip on the coldest days?

Intake air is coldest, filters may be wet or iced, and the burner is at highest demand. Service before the snap.

Who do we call in Preston?

AAC Gas: 01772 382971. 24/7: 07592 333187. Email: info@aacgas.co.uk.

If the doors stay open, heat the air that comes in

Book make-up air heater servicing with your winter warehouse visit. AAC Gas will tell you whether MUA is doing its job.

Call 01772 382971 or 07592 333187 (24/7 emergency), or email info@aacgas.co.uk.

Covering Preston, Walton Summit, Bamber Bridge, Leyland, Chorley and Lancashire warehouse sites.